Does scale matter? The costs of HIV-prevention interventions for commercial sex workers in India

Transcription

1 Does scle mtter? The costs of HIV-prevention interventions for commercil sex workers in Indi Lorn Guinness, 1 Lilni Kumrnyke, 1 Bhuvneswri Rjrmn, 2 Girij Snkrnrynn, 3 Gngdhr Vnnel, 4 P. Rghupthi, 5 & Alex George 4 Ojective To explore how the scle of project ffects oth the totl costs nd verge costs of. Methods Economic cost dt nd mesures of scle (coverge nd service volume indictors for numer of cses of sexully trnsmitted infections (STIs) referred, numer of STIs treted, condoms distriuted nd contcts mde with trget groups) were collected from 17 interventions run y nongovernmentl orgniztions imed t commercil sex workers in southern Indi. Nonprmetric methods nd regression nlyses were used to look t the reltionship etween totl costs, unit costs nd scle. Findings Coverge vried from 250 to 2008 sex workers. Annul costs rnged from US$ to US$ The medin cost per sex worker reched ws US$ (rnge = US$ ). The scle vriles explin more thn 50% of the vrition in unit costs for ll of the unit cost mesures except cost per contct. Totl costs nd unit costs hve non-liner reltionships to scle. Conclusion Averge costs vry with the scle of the project. Estimtes of resource requirements sed on constnt verge cost could underestimte or overestimte totl costs. The results highlight the importnce of improving scle-specific cost informtion for plnning. Keywords HIV infections/prevention nd control/economics; Prostitution; Sexully trnsmitted diseses/therpy; Contct trcing/ economics; Condoms/economics; Costs nd cost nlysis; Indi (source: MeSH, NLM). Mots clés Infection à VIH/prévention et contrôle/économie; Prostitution; Mldies sexuellement trnsmissiles/thérpeutique; Recherche sujet contct/économie; Condom/économie; Coût et nlyse coût; Inde (source: MeSH, INSERM). Plrs clve Infecciones por VIH/prevención y control/economí; Prostitución Enfermeddes sexulmente trnsmisiles/terpi; Trzdo de contcto/economí; Condones/economí; Costos y nálisis de costo; Indi (fuente: DeCS, BIREME). Bulletin of the World Helth Orgniztion 2005;83: Voir pge 754 le résumé en frnçis. En l págin 754 figur un resumen en espñol..754 Introduction UNAIDS hs highlighted the urgent need to scle-up prevention progrmmes s glol funding for tretment nd cre for people living with AIDS increses. The understnding of the resource requirements needed to expnd these ctivities hs improved t the glol level s result of costings mde y UNAIDS nd the Commission on Mcroeconomics nd Helth (1 3). However, these estimtes still lck stndrdized dtsets on cost structures for prticulr interventions t different scles of ctivity nd in different environments. Improving the understnding of resource requirements is criticl to identifying the cost implictions of efforts to expnd ongoing prevention services included in the work of the Glol Fund to Fight AIDS, Tuerculosis nd Mlri; the World Bnk s Multi-Country HIV/AIDS Progrm for Afric; nd the World Helth Orgniztion s 3 y 5 inititive. Economic theory hypothesizes tht s scle increses, totl costs increse t chnging rte, giving rise to the clssic U-shped verge cost curve. This curve results from certin inputs vrying with the level of output (such s the cost of condoms or drugs) nd, in the short run, other costs remining fixed (such s overheds nd uilding costs). As the scle increses, fixed costs re shred over n incresing numer of outputs until they rech the limit of their cpcity. This shring of fixed costs leds to non-linerities in the reltionship etween totl costs nd scle. Evidence from other helth services supports the theory of non-linerities nd suggests tht costs vry with scle s well s with numer of other contextul, orgniztionl nd intervention-specific fctors (4 12). In Indi, where n estimted 5.1 million people re living with HIV or AIDS (13), the Ntionl AIDS Control Progrmme, under the direction of the Ntionl AIDS Control 1 Deprtment of Pulic Helth nd Policy, London School of Hygiene nd Tropicl Medicine, Keppel Street, London WC1E 7HT, Englnd. Correspondence should e sent to Dr Guinness t this ddress (emil:lorn.guinness@lshtm.c.uk). 2 Indin Institute of Technology (Mdrs), Indi. 3 Emory University, Atlnt, GA, USA. 4 Centre for Helth nd Socil Sector Studies, Hyderd, Andhr Prdesh, Indi. 5 University of Hyderd, Andhr Prdesh, Indi. Ref. No (Sumitted: 13 August 2004 Finl revised version received: 10 Decemer 2004 Accepted: 10 Jnury 2005) Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10) 747

2 Reserch Orgniztion, hs contrcted with nongovernmentl orgniztions (NGOs) to trget HIV prevention towrds higher-risk groups (14 17, nd Ntionl AIDS Control Orgniztion, unpulished guidelines, 2000). Dt on the costs of these inititives re scrce (18, nd D Wilson. Review of the Helthy Highwys Project, unpulished report, 1999; V Gonzles et l. Midterm evlution of West Bengl Sexul Helth Project, unpulished report, 1999); there is little informtion to drw on from elsewhere (4, 19, 20); nd there is limited evidence on how totl costs chnge s ctivities expnd (21). In nlysing the costs of 17 HIV-prevention interventions trgeted t commercil sex workers in southern Indi, this pper explores how scle ffects site-specific totl costs nd verge costs of HIV prevention. It is the first pper to present cost dt collected from multiple sites for single HIV-prevention intervention. The nlysis ddresses previous prolems of methodologicl nd definitionl differences nd vritions in input vlution, which reserchers often fce when using cost informtion from different studies (4, 20, 22), y using stndrdized method cross the sites. It is therefore le to explore how costs vry with scle. Methods Smple selection A cse-study pproch ws used to enle in-depth insights s well s collection of full economic costs. Seventeen NGOs were selected from the 259 trgeted interventions identified in census survey of interventions in Andhr Prdesh nd Tmil Ndu (Tle 1, ville only on the we t int/ulletin). Both sttes hd contrcted with NGOs on lrge scle (i.e., for more thn 50 interventions). Interventions were purposively smpled ccording to their cpcity, the funding gency, their geogrphicl loction, experience in implementing HIV interventions nd willingness to prticipte. Only interventions imed t commercil sex workers were selected in order to control for differences in intervention ctivities, epidemiology nd trget popultions. Similrities in intervention design were further ensured y the Ntionl AIDS Control Orgniztion s prescription of key components: informtion nd eduction on ehviourl chnge, condom distriution, peer eduction, mngement of sexully trnsmitted infections (STIs), nd creting n enling environment for the intervention (23, 24, nd Ntionl AIDS Control Orgniztion, unpulished guidelines, 2000). Dt collection Economic dt on providers costs were collected for the finncil yer ; dt included informtion on costs incurred t the intervention-level nd funding-gency level. Economic costs include ll inputs involved in the intervention nd vlue them t their opportunity cost (including inputs tht re donted or susidized). This provides stndrdized method for dt collection, enling vlid cost comprisons cross the interventions. The ingredients pproch to costing ws used s fr s possile (see, for exmple, (5)). Mesuring scle Scle is defined from n economic perspective tht is, it is the extent or level of ctivity t which n intervention is operting (25, 26). Coverge, which is mesured y the numer of people reched, reflects scle s defined y ntionl policy. Another six indictors reflect different spects of the volume of Lorn Guinness et l. services delivered: numer of commercil sex workers referred for STI tretment, numer of STIs treted, numer of condoms distriuted, numer of first contcts mde with memers of the trget group, totl numer of contcts mde with memers of the trget group nd totl numer of contcts with the memers of the community. All scle mesures were otined from NGO s routine monitoring systems. Input identifiction Inputs were identified y reviewing project documenttion, y interviewing project personnel nd y scertining locl mrket prices (Appendix 1, ville only on the we t who.int/ulletin). They were clssified s fixed or vrile, ccording to stndrd economic definitions (5). Where quntities were not ville, expenditures were used to represent input levels. Becuse methods of STI mngement vried, this ws considered n input ctegory in itself. Funding gency-level inputs were llocted to the interventions using direct lloction methods (27). Cost vlution All costs were vlued t locl mrket prices. Peer eductors time nd costs were scertined through simple idding gme tht generted vlues which were then vlidted in interviews with outrech stff. Condoms distriuted free of chrge were vlued t the price of the lowest cost lterntive in the mrket tht is, susidized socilly mrketed condom. Becuse there were Tle 3. Chrcteristics of 17 HIV-prevention interventions run y selected nongovernmentl orgniztions (NGOs) nd trgeted t sex workers, Tmil Ndu nd Andhr Prdesh, Indi. Vlues re numers (%), unless otherwise indicted Chrcteristics of the interventions Distriution Intervention design STI tretment Referrl 15 (88) NGO s own clinic 2 (12) Context Tmil Ndu 8 (47) Andhr Prdesh 9 (53) Medin % (rnge) litercy 73 (59 85) Medin (rnge) length of time project 6 (3 13) under wy (yers) Cpcity Certified to receive foreign funds No certificte 3 (17.6) Certified 14 (82.4) Medin No. (rnge) of stff working 39.3 ( ) on HIV (n = 16) Medin (rnge) nnul expenditure 51.6 ( ) (US$ 000) (n = 14) Finncing Funding gency A 9 (52.9) B 2 (11.8) C 2 (11.8) D 4 (23.5) Medin (rnge) HIV project udget (US$ 000) (n = 15) 15.5 ( ) n = 17 unless otherwise specified. 748 Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10)

3 Lorn Guinness et l. no dt on revenues, the net cost of condom sles (i.e., the cost of condom procurement minus revenue from sles) ws ssumed to e 0. Annulized economic costs were clculted using stndrd discount rte of 3% (see, for exmple, (27)). Cpitl items were ssumed to hve life of etween 3 nd 10 yers, depending on the item. All costs were converted to constnt Indin rupees, using the GDP (Gross Domestic Product) defltor, nd then converted to US dollrs (US$ 1.00 = 42 rupees) (28). Anlysis Scle, totl costs, cost structures nd unit costs (totl costs divided y scle vrile) were compred cross the interventions. Due to the smll smple size, non-prmetric methods were used to look t the reltionship etween scle nd the two cost vriles: totl costs nd unit costs. The cost vriles were regressed on scle, compring liner nd qudrtic eqution forms. Non-prmetric methods were lso used to look t whether scle, totl costs nd unit costs re ffected y fctors including the stte where the intervention took plce, the funding gency, the method of STI mngement, district litercy levels, length of time the project hs een under wy, the intervention s udget nd the NGO s cpcity. Two tests were used: the medin test for ctegoricl explntory vriles (reported s Person s χ²) nd Spermn s rnk order correltion coefficient (r s ) test for independence of smples for the continuous explntory vriles (see, for exmple, (29)). The null hypothesis for ech test ws tht there ws no reltionship etween scle vriles or cost vriles nd the explntory vrile. Reserch Sensitivity nlysis Due to the retrospective nture of the study, severl constrints were fced in dt collection: some dt were missing; there were inccurcies in the dt; nd sometimes prices hd to e used in plce of cost. One-wy sensitivity nlysis ws used to ccount for these limittions y mnully chnging vlues in the costing spredsheets (Tle 2, ville t int/ulletin) nd generting rnges of totl costs nd unit costs for ech intervention. The non-prmetric tests nd regressions were then run gin to explore whether reltionships still held when extreme vlues were used. Findings NGO chrcteristics Chrcteristics of the selected NGOs re descried in Tle 3. Of the smple, 8 were in Tmil Ndu nd 9 were in Andhr Prdesh. Four different funding gencies were represented in the smple. District litercy rtes rnged from 60% to 85%. The NGOs totl nnul expenditures rnged from US$ 5324 to US$ 1.1 million, with the proportion of stff working on HIV representing etween 5% nd 95% of ll stff. Three NGOs were not certified to receive foreign funds. The length of time the intervention hd een under wy vried from 3 to 13 yers. Two of the interventions provided STI services t their own clinics; 12 NGOs referred people for tretment ut susidized their tretment; nd 3 mde referrls only. Totl costs nd cost profiles Totl costs nd their rekdown re descried in Tle 4. The medin totl cost ws US$ (rnge = US$ ). Tle 4. Totl costs nd cost profiles of 17 HIV-prevention interventions run y selected nongovernmentl orgniztions (NGOs) nd trgeted t sex workers, Tmil Ndu nd Andhr Prdesh, Indi Cost ctegory Costs (US$ 000) Medin Minimum Mximum Fixed personnel 3.63 (15.7) c 1.08 (6.5) 8.27 (22.6) Trining 0.12 (0.6) (3.2) Monitoring 0.55 (1.9) 0.03 (0.2) 0.92 (3.6) Building nd office costs 2.57 (12.7) 0.46 (3.6) 5.29 (26.1) Vehicles 0.07 (0.4) 0 (0) 2.37 (10.4) Totl fixed 6.80 (34.1) 1.71 (13.5) (40.6) Vrile personnel 4.62 (19.7) 1.28 (10.4) 6.49 (28.9) Peer eductors 2.16 (9.9) 0.34 (1.2) (34.9) Informtion, eduction nd communiction mterils 0.38 (1.3) 0.01 (0.1) 2.21 (12.8) STI tretment d 0.71 (3.3) 0 (0) 2.33 (10.7) Condoms 0.85 (3.8) 0.01 (0.1) 7.37 (18.8) Meetings 0.72 (3.5) 0.08 (0.4) 2.32 (8.8) Trnsport 1.36 (4.6) 0.15 (1.2) 2.45 (9.3) Other 0.40 (1.3) 0 (0) 1.62 (5.3) Totl vrile (53.2) 4.48 (39.7) (70.7) Totl NGO (88.5) 6.78 (60.1) (95.3) Agency 2.51 (11.5) 1.53 (4.7) 4.50 (39.9) Totl (100.0) (100.0) (100.0) The minimum numer of commercil sex workers reched y n intervention ws 250; the medin ws 1047; the mximum ws Costs re in prices. c Vlues in prentheses re the medin, minimum nd mximum vlues for the percentges of totl costs in ech cost ctegory. d STI = sexully trnsmitted infection. Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10) 749

4 Reserch Lorn Guinness et l. Tle 5. Coverge, volume per commercil sex worker reched nd non-prmetric tests for fctors influencing scle vriles for the 17 HIV-prevention interventions run y selected nongovernmentl orgniztions (NGOs) nd trgeted t commercil sex workers, Tmil Ndu nd Andhr Prdesh, Indi Intervention chrcteristic Unit Smple Reltionship with size coverge (Spermn s r s) Sex workers reched y the intervention (n = 17) ( ) People referred to helth-cre providers y the project 0.37 d ( ) for consulttion on STI c (n = 17) People treted for STIs y the project or s result 0.32 d ( ) e of the project s referrls or susidies (n = 15) Condoms distriuted for free nd through NGO sles (n = 17) d ( ) First-time project contcts with memers of the trget group (n = 14) 0.71 d ( ) f Contcts with memers of the trget group (first nd repet) (n = 11) 3.43 d ( ) Contcts with memers of the trget group plus contcts 3.83 d ( ) with the roder community (first nd repet) (n = 11) Budget e Project ge NGO expenditure HIV stff shre Litercy e Person s χ² Stte Funding gency e Certified to receive foreign funds STI service provision Vlues in this column re medin (rnge). Vlues in this column mesure the strength of the reltionship etween the vriles: the closer r s is to + /-1.0, the stronger the reltionship etween the two continuous vriles; the higher the solute vlue of χ², the stronger the correltion etween the continuous nd the ctegoricl vriles. c STI = sexully trnsmitted infection. d Vlue is per person reched. e P < f P < 0.01 The levels t which costs re incurred nd the cost profiles lso vry. The medin vlue of the proportion of costs incurred t the gency level (11.5%) hides wide vrition cross NGOs, from 5% to 39.9%. Vrile costs rnge from 40% to 71% of totl costs, with medin vlue of 53.2%. Personnel (stff time) costs re the lrgest portion of vrile costs nd rnge from 10% to 29%. On verge the cost of peer eduction is the next lrgest prt of vrile costs (9.9%). The cost of peer eductors lso hs the lrgest vrition in reltive contriution to the intervention. Although peer eductors could e sustitute for or complement to stff, no reltionship, on verge, is oserved etween the cost of peer eductors nd stff costs (r s = ; proility t < 1 = ). The cost of STI tretment ppers to vry with the different methods of mngement; the proportion of costs ttriutle to STI tretment ws highest t the two sites tht provided clinic services. This reltionship is not significnt (Person s χ² = ; proility t < 1 = 0.2) indicting tht other fctors influence this prt of the cost rtio, e.g. the shre of peer-eductor costs is low where the shre of STI tretment costs is high. There is wide vrition in the reltive costs of condoms, from 0.1% to 19% of totl costs. Profiles of fixed costs lso show vriility, rnging from 13.5% to 41% of totl costs. Personnel nd uilding costs (including rent nd mintennce nd ll expenses ssocited with running n office) re the most importnt fixed costs, with medin vlues of 16% nd 12%, respectively. Although trining costs pper to e low, the mjority of these costs re incurred t the gency level, comprising etween 6% nd 28% of gency costs. Scle of the interventions In terms of coverge, interventions reched from 250 to 2008 commercil sex workers (Tle 5), nd non-prmetric tests show tht there re significnt reltionships etween coverge nd funding gency, udget (positive) nd litercy rte (negtive). Becuse coverge levels vry cross the interventions, comprisons of service volume were mde y first dividing the volume descriptors y coverge, thus reveling lrge vritions in service volume. Although reltionship etween volume nd coverge ws expected, no significnt reltionship ws oserved, except in the cse of numer of STIs treted. Averge costs of the interventions Unit costs of the intervention re descried in Tle 6. The cost per person reched rnges from US$ 9.86 to US$ The medin vlue is US$ Vrition is lso evident in the cost per unit of volume of services, e.g. the medin cost per STI treted is US$ (rnge = US$ ) nd the cost per first contct with the trget group is US$ (rnge = US$ ). 750 Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10)

5 Lorn Guinness et l. Reserch Tle 6. Reltionship etween totl costs, unit costs nd scle for 17 HIV-prevention interventions run y selected nongovernmentl orgniztions (NGOs) nd trgeted t commercil sex workers, Tmil Ndu nd Andhr Prdesh, Indi Mesure of scle Totl costs Unit costs (US$ 000) Medin (rnge) Spermn s rho (r s) Coverge (n = 17) c ( ) c Sexully trnsmitted infections referred (n = 17) c ( ) c Sexully trnsmitted infections treted (n = 14) d ( ) c Condoms distriuted (n = 17) d 0.22 ( ) c First contcts with trget group (n = 15) d ( ) c All contcts with trget group (n = 11) ( ) c All contcts (n = 11) d 4.68 ( ) Medin totl cost (rnge) in US$ 000s ( ) Vlues in this column mesure the strength of the reltionship etween unit cost nd the respective unit of scle: the closer r s is to + /-1.0, the stronger the reltionship etween the two continuous vriles. Vlues re constnt prices. c P < d P < 0.01 Anlysis of cost vrition Totl cost hd sttisticlly significnt nd positive reltionships with oth coverge nd ll ut one of the indictors of volume (ll contcts with the trget group) (Tle 6). Fig. 1 shows how totl costs increse with coverge nd suggests tht totl costs do not increse linerly. The qudrtic model hs higher R² (mesure of goodness of fit of the regression) thn the liner form, supporting the hypothesis. The qudrtic reltionship etween totl costs nd scle lso pplies to the volume indictors except condoms distriuted, ll contcts with trget groups nd ll contcts. The regressions imply tht there is positive liner reltionship etween condoms nd totl costs. However, neither the liner model nor the qudrtic model is good fit for the reltionships etween the contct vriles (F is not significnt nd R² < 0.1). The null hypothesis (tht there is no reltionship etween unit cost nd mesures of scle) cn lso e rejected. The results of the non-prmetric tests of cost per unit of scle ginst the respective scle unit re ll negtive nd, with the exception of ll contcts, sttisticlly significnt (Tle 6). The scle vriles explin more thn 70% of the vrition in unit costs for ll mesures of unit costs except cost per sex worker reched nd cost per contct. The influence of the fctors, descried in Tle 3, on unit costs ws lso tested using non-prmetric methods (see Appendix 2 nd Appendix 3, ville only on the we t We could not reject the null hypothesis of no reltionship except for negtive reltionship etween udget nd the cost per condom distriuted, positive reltionship etween the length of time the project hd een under wy nd the cost per sex worker referred for STI tretment or the cost per STI treted, positive reltionship etween the price of field workers nd the cost per contct, nd positive reltionship etween the price of peer eductors nd the cost per STI referred. The regressions of unit costs ginst scle suggested nonliner reltionships except in the cse of ll contcts (Fig. 2). In looking t the fitted regression line of cost per sex worker reched ginst coverge, we oserved fitted line resemling Fig. 1. Regression: ) Liner nd ) qudrtic forms of totl costs ginst scle of HIV-prevention interventions trgeted t commercil sex workers (CSWs). (Vlues re for prices; dditionl sttisticl informtion is ville t the following URL: ) ) Totl nnul cost (x 10 3 US$) No. of CSWs reched Totl nnul cost (x 10 3 US$) No. of CSWs reched 95% confidence intervls Totl nnul cost 000s US$ Fitted vlues WHO Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10) 751

6 Reserch Lorn Guinness et l. Fig. 2. Fitted regression: ) Liner nd ) qudrtic forms of costs per unit of scle for the HIV-prevention interventions trgeted t commercil sex workers (CSWs). (Vlues re prices; dditionl sttisticl informtion is ville t the following URL: ) ) Cost per CWS reched (x 10 3 US$) No. of CSWs reched Cost per CWS reched (x 10 3 US$) No. of CSWs reched 95% confidence intervls Totl nnul cost 000s US$ Fitted vlues WHO clssic U-shped verge cost curve in which there is costminimizing level of coverge in the rnge of sex workers reched. The sensitivity nlysis generted rnges for the totl costs etween 10% nd 40% of the vlue in the originl nlysis. Similrly, the rnge of unit costs ws etween 10% nd 43% of the originl vlues. The est-fit regression models for cost per person reched (Fig. 3) nd cost per mesure of volume held when they were run gin with these extreme vlues. Discussion The cost nlysis of trgeted HIV-prevention interventions presented here explores how costs vry cross similr interventions, with prticulr focus on how costs vry ccording to the scle of the intervention. Differences were found in the scle, totl costs, cost structures nd verge costs. Both totl costs nd verge costs were found to hve significnt reltionships with the scle vriles. These reltionships were not liner. Despite the lrge contriution of vrile costs to the cost structure, verge costs vry with scle: point where verge costs egin to rise is reched t reltively low levels of coverge. This nlysis is limited y eing retrospective nd y its use of routine monitoring systems not specificlly designed for cost nlyses. In some cses, inputs nd vlues to the project were estimted sed on interviews rther thn records. Outputs were tken from routine monitoring systems, nd these cn e suject to errors. Finncil dt were used s proxy for the economic costs of trnsport nd monitoring owing to lck of records. The smll smple, compounded y the diversity in the orgniztions chrcteristics, limits our ility to llow confident inference from the non-prmetric nd regression nlyses. Therefore, interprettions of the results should e mde with cution. In ddition, it is not possile to determine Fig. 3. Sensitivity nlysis plots of qudrtic reltionship etween coverge of commercil sex workers (CSWs) nd ) totl costs nd ) cost per person reched. (Additionl sttisticl informtion is ville t the following URL: ) ) Totl nnul cost (x 10 3 US$) Cost per CSW reched (x 10 3 US$) No. of CSWs reched No. of CSWs reched Mximum vlues of cost Medin vlues of cost Minimum vlues of cost WHO Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10)

7 Lorn Guinness et l. the strength of the reltionships of scle with the other dimensions ecuse multivrite nlysis would e required. In spite of these prolems, the one-wy sensitivity nlysis showed the results to e quite roust. Although there my lso e is resulting from the necessry smpling criteri of greement to prticipte, the direction of this is is miguous, i.e. those greeing to prticipte re likely to e etter t reporting nd this my or my not imply tht the smple hs verge costs tht re consistently lower or higher. Vritions in scle my rise from the length of time the intervention hs een under wy, the rechility nd size of the trget group s well s the trgets set y the contrcting gent. Coverge vried ccording to the funding gency nd the udget. Becuse nnul udgets depend on chievements mde during the previous yer nd, t the time of the study, there ws limited informtion on the size of the trget popultions, it is likely tht coverge reflects the ility to negotite trgets rther thn the ctul size of the popultion. This my lso pply to differences in volume with respect to coverge: for one funding gency, STI trgets nd udgets were set ccording to the greed coverge of trgets. However, these mesures lso confirm the degree of vrition in technicl efficiency (cost per unit of output) cross pprently similr interventions. As with scle, totl costs re likely to e driven y udgets nd trgets set y the orgniztions. Further nlysis finds tht of the fctors shown in Tle 3, only funding gency hd significnt reltionship with totl cost (Person s χ² = ; proility t < 1 = 0.004). A wide rnge of fctors hs lso een found to influence verge costs including scle, intervention design, context, cpcity, project ge, inefficiencies nd prices (5 8, 10 12, 19, 30 33). In order to fcilitte the comprisons etween costs nd scle of opertion, the smpling procedure controls for epidemiology, intervention design nd context s fr s possile. Inevitly, s the smple is tken from n ctive progrmme, these fctors vry cross the interventions. For exmple, two of the 17 interventions provided STI services within their own clinics. Other interventions referred people for tretment nd, except for three interventions, provided susidy to the provider. Although this my limit the comprility of the interventions, it reflects the relity of scling-up in which there will lwys e vrition in the design of the intervention. The context of the interventions lso vried. The interventions exmined took plce in two different sttes nd were funded y four different orgniztions. Despite these differences, the nlysis found tht these contextul fctors nd intervention chrcteristics hd no influence on unit costs (see Appendix 2 nd Appendix 3) nor did the non-prmetric tests llow us to reject the hypothesis tht there is no reltionship etween prices nd verge costs (Appendix 3). It ws not possile to identify inefficiencies ssocited with different levels of performnce in quntifile form. The nlysis confirms tht scle is key fctor in influencing the unit cost, resulting in U-shped verge cost curve. Due to the limittions of the dt, the cost function is not derived from production function ut is descriptive. This mkes it more difficult to identify the cuses of chnge in verge cost nd to explin the reltionship etween costs nd scle. Appendix 4 (ville only on the we t looks t the reltionship etween cost structure nd coverge. Appendix 4 shows tht the percentge Reserch Fig. 4. Reltionship etween cost structure nd coverge of the interventions Medin % of totl cost Fixed personnel Building office costs Vrile personnel Input ctegory of costs spent t the funding gency-level flls s coverge increses, ut no other trends re discernle, emphsizing the context-specific nture of costs nd the need for further reserch into the economics of the design nd implementtion of HIV prevention services. The chnging nture of the verge cost hs importnt implictions for plnning the resources needed for scling-up interventions. Contrry to expecttions tht the high proportion of vrile costs would led to constnt verge costs nd the resource estimtion techniques tht ssume this, verge costs fll nd then rise gin s coverge increses. Estimtes of resource requirements tht re sed on constnt verge cost would therefore significntly underestimte or overestimte the totl costs. The results of this study, derived from unique set of dt on the costs of HIV prevention services cross multiple sites, highlight the importnce of using scle-specific cost informtion in order to identify the optiml size of n intervention nd to improve estimtes of resource requirements. O Acknowledgements We thnk Dr Kr Hnson nd two nonymous reviewers for their invlule comments, Professor V R Murleedhrn, Indin Institute of Technology (Mdrs) nd Professor Chrles Normnd for their continued support, s well s ll the prticipting NGOs nd their funding gencies for their extensive coopertion. Funding: This reserch ws funded y the Wellcome Trust, United Kingdom. Lorn Guinness is Wellcome Trust Reserch Fellow t the London School of Hygiene nd Tropicl Medicine nd lso memer of the Helth Economics nd Finncing Progrmme, which receives funds from the Deprtment For Interntionl Development of the United Kingdom (DFID). Lilni Kumrnyke is memer of the Deprtment for Interntionl Development of the United Kingdom-funded Tuerculosis nd AIDS/STI Knowledge Progrmmes t the London School of Hygiene nd Tropicl Medicine. DFID supports policies, progrmmes nd projects to promote interntionl development. The views nd opinions expressed re those of the uthors lone. Competing interests: none declred. High cost, low coverge Mid-cost, low coverge Mid-cost, low coverge High cost, high coverge Peer eductors Agency Totl personnel WHO Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10) 753

8 Reserch Lorn Guinness et l. Résumé Coûts des interventions visnt à prévenir l trnsmission du VIH chez les trvilleurs du sexe indiens : influence de l échelle du projet Ojectif Étudier l impct de l échelle d un projet sur les coûts professionnels du sexe. Les coûts nnuels se situient entre totux et moyens de l prévention de l trnsmission du VIH en US $ et US $ Le coût médin pr trvilleur du sexe Inde. tteignit US $ 19,21 (plge de vrition : US $ 10,00 à 51,00). Méthodes Pour 17 interventions gérées pr des orgnistions non Les vriles d échelle permettient de justifier plus de 50 % de l gouvernementles et visnt les professionnels du sexe du sud de vrition des coûts unitires pour l ensemle des mesures de coût l Inde, on recueilli des données reltives ux coûts et des mesures unitire, éxcepté le coût pr contct. Les coûts totux et les coûts de l échelle du projet [couverture et indicteurs du volume de unitires sont reliés à l échelle pr une reltion non linéire. services correspondnt ux nomres de cs d infections sexuellement Conclusion Les coûts moyens vrient vec l échelle du projet. trnsmissiles (IST) dressés, d IST tritées, de préservtifs distriués Les estimtions des esoins en ressources se fondnt sur un coût et de contcts noués vec les groupes ciles]. L reltion entre coûts moyen constnt pourrient donc conduire à une sous-estimtion totux, coûts unitires et échelle du projet été nlysée pr des ou à une surestimtion des coûts totux. Les résultts de l étude méthodes non prmétriques et des nlyses pr régression. font ressortir l importnce pour l plnifiction d une meilleure Résultts L couverture des interventions llit de 250 à informtion sur les coûts dépendnt de l échelle du projet. Resumen L escl, un fctor importnte? Costo de ls intervenciones de prevención de l infección por VIH entre los profesionles del sexo en l Indi Ojetivo Estudir cómo influye l escl de un proyecto tnto sexo. Los costos nules oscilron entre US$ y US$ en los costos totles como en los costos medios de l prevención L medin del costo por profesionl del sexo lcnzdo fue de de l infección por VIH en l Indi. US$ 19,21 (intervlo: US$ 10,00-51,00). Ls vriles indictivs Métodos A prtir de 17 intervenciones emprendids por de l escl explicn más del 50% de l vrición de los costos orgnizciones no guernmentles entre profesionles del unitrios pr tods ls medids del costo unitrio, exceptundo el sexo en el sur de l Indi, se reunieron dtos sore los costos costo por contcto. Los costos totles y los costos unitrios están económicos e indicdores de l escl de l intervención (coertur relciondos de mner no linel con l escl. y volumen de servicios pr el número de csos de infecciones Conclusión Los costos medios vrín con l escl del proyecto. de trnsmisión sexul (ITS) remitidos, número de ITS trtds, Ls estimciones de ls necesiddes de recursos sds en un número de preservtivos distriuidos y contctos hidos con costo medio constnte tienden suestimr o sorestimr los los grupos destintrios). L relción entre los costos totles, los costos totles. Los resultdos destcn l importnci de mejorr costos unitrios y l escl se determinó medinte métodos no l informción sore los costos en función de l escl efectos prmétricos y nálisis de regresión. de plnificción. Resultdos L coertur vrió entre 250 y profesionles del 754 Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10)

9 Lorn Guinness et l. References 1. Schwrtlnder B, Stover J, Wlker N, Bollinger L, Gutierrez JP, McGreevey W, et l. Resource needs for HIV/AIDS. Science 2001;292: Commission on Mcroeconomics nd Helth. Mcroeconomics nd helth: investing in helth for economic development. Genev: World Helth Orgniztion; UNAIDS. Report on the glol AIDS epidemic. Genev: UNAIDS; Creese A, Floyd K, Aln A, Guinness L. Cost effectiveness of HIV/AIDS interventions in Afric: review of the evidence. Lncet 2002; 359: Creese A, Prker D. Cost nlysis in primry helth cre: trining mnul for progrmme mngers. Genev: World Helth Orgniztion; Gilson L. Vlue for money? The efficiency of primry helth units in Tnzni [thesis]. London: University of London, Fculty of Medicine; Mnsley EC, Dunet DO, My DS, Chttopdhyj SK, McKenn MTM. Vrition in verge costs mong federlly sponsored stte-orgnized cncer detection progrms: economies of scle? Med Decis Mking 2002;22 Suppl 5:S Over M. The effect of scle on cost projections for primry helth cre progrmme in developing country. Soc Sci Med 1986;22: Roertson RL, Dvis JH, Joe K. Service volume nd other fctors ffecting the costs of immuniztions in the Gmi. Bull World Helth Orgn 1984;62: Roertson RL, Hll AJ, Crivelli PE, Lowe Y, Inskip HM, Snow SK. Costeffectiveness of immuniztions: the Gmi revisited. Helth Policy Pln 1992;7: Stllworthy G, Meekers D. An nlysis of unit costs in selected condom socil mrketing progrmmes Proceedings of XII Interntionl Conference on AIDS. Genev: Congrex; 1998 (Astrct No. 467/44240). 12. Grieve R, Dunds R, Beech R, Wolfe C. The development nd use of method to compre the costs of cute stroke cross Europe. Age Ageing 2001;30: UNAIDS. Tle of country-specific HIV/AIDS estimtes nd dt, end In: 2004 report on the glol AIDS epidemic. Genev: UNAIDS; Rmsundrm S, Alludin K, Chrles B, Gopl K, Krishnmurthy P, Poornlingm R, et l. HIV/AIDS control in Indi lessons lerned from Tmil Ndu. Genev: Commission on Mcroeconomics nd Helth; 2001 (Working pper No. WG5:25). (Also ville from org/docs/wg5_pper25.pdf.) 15. Rmsundrm S. Cn Indi void eing devstted y HIV? Yes, y scling up locl prevention efforts trgeted t the most vulnerle groups. BMJ 2002;324: Ntionl AIDS Control Orgniztion. Comting HIV/AIDS in Indi, New Delhi: Ministry of Helth nd Fmily Welfre, Ntionl AIDS Reserch Control Orgniztion, Government of Indi; World Bnk Nutrition nd Popultion Sector Unit, South Asi Region. Project pprisl document on proposed credit in the mount of SDR million to Indi for second ntionl HIV/AIDS control project. Wshington, DC: World Bnk; p Ntionl AIDS Control Orgniztion, UNAIDS. Costing of focused interventions mong different su-popultions. Delhi: UNAIDS, South Asi; Kumrnyke L, Wtts C. Economic costs of HIV/AIDS prevention ctivities in su-shrn Afric. AIDS 2000;14 Suppl 3: S Wlker D. Cost nd cost-effectiveness of HIV/AIDS prevention strtegies in developing countries: is there n evidence se? Helth Policy Pln 2003; 18: Kumrnyke L, Wtts C. HIV/AIDS prevention nd cre interventions in su-shrn Afric: n econometric nlysis of the costs of scling-up. S Afr J Econ 2000;68: Soderlund N, Lvis J, Broomerg J, Mills A. The costs of HIV prevention strtegies in developing countries. Bull World Helth Orgn 1993;71: Jn S, Bndyopdhyy N, Mukherjee S, Dutt N, Bsu I, Sh A. STD/HIV intervention with sex workers in West Bengl, Indi. AIDS 1998;12: Jenkins C. Femle sex worker HIV prevention projects: lessons lernt from Ppu New Guine, Indi nd Bngldesh. Genev: UNAIDS; Kumrnyke L, Wtts C. Costs of scling HIV progrm ctivities to ntionl level for su-shrn Afric: methods nd estimtes.:wshington, DC: AIDS Cmpign Tem for Afric (ACTfric), World Bnk; De Jong J. Mking n impct in HIV nd AIDS: NGO experiences of scling up. London: ITDG; Drummond M, Stoddrt GL, Torrnce GW. Methods for the economic evlution of helth cre progrmmes. Oxford: Oxford Medicl Pulictions; Reserve Bnk of Indi. Hndook of sttistics for Indi. New Delhi: Reserve Bnk of Indi; 2003 (Also ville from index.dll/7?opensection?fromdte=06/07/2003&todte=06/07/ 2003&s1secid=1001&s2secid=1001). 29. Pett M. Nonprmetric sttistics for helth cre reserch: sttistics for smll smples nd unusul distriutions. London: Sge; Fiedler J, Dy L. A Cost nlysis of fmily plnning in Bngldesh. Int J Helth Plnn Mnge1997;12: Brnum H, Kutzin J. Pulic hospitls in developing countries: resource use, costs nd finncing. Bltimore, MD: Johns Hopkins University Press; Bermn P. Cost nlysis s mngement tool for improving the efficiency of primry cre: some exmples from Jv. Int J Helth Plnn Mnge 1986; 1: Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10) 755

10 Lorn Guinness et l. Reserch Tle 1. Chrcteristics of popultions of Tmil Ndu nd Andhr Prdesh, Indi, Chrcteristic Stte Source Andhr Prdesh Tmil Ndu Totl popultion Census of Indi % living in rurl res Census of Indi Per cpit income, prices (Indin rupees) South Indi humn development report % of popultion tht is literte c Census of Indi Access to helth services (1991) Doctors/ popultion South Indi humn development report Prmedics/ popultion South Indi humn development report Helth sttus ( ) Infnt mortlity rte/1 000, urn res South Indi humn development report Infnt mortlity rte/1 000, rurl res South Indi humn development report Reported AIDS cses (s of 31 Mrch 2005) Monthly updtes on AIDS d HIV prevlence (% of popultion), 2000 Attendees t sexully trnsmitted infection clinics Comting HIV/AIDS in Indi e Attendees t ntentl clinics Comting HIV/AIDS in Indi Injecting drug users Not ville Comting HIV/AIDS in Indi Men who hve sex with men Not ville 2.4 Comting HIV/AIDS in Indi Commercil sex workers 48.5 (Kkind, 2000) 54.7 Strtegic pln of the Andhr Prdesh stte 43.9 (Peddpurm, 2000) AIDS control progrmme f Numer of government-supported trgeted Prtnering with NGOs g interventions for high-risk groups Registrr Generl, Census Commissioner of Indi. Census of Indi, 2001 ( Ntionl Council of Applied Economic Reserch. South Indi humn development report. New Delhi: Oxford University Press; c Litercy is defined s eing le to oth red nd write, with understnding, short, simple sttement on everydy life. d Ntionl AIDS Control Orgniztion. Monthly updtes on AIDS, 2005 ( e Ntionl AIDS Control Orgniztion. Comting HIV/AIDS in Indi , 2001 ( f D Wilson et l. Strtegic pln of the Andhr Prdesh stte AIDS control progrmme, unpulished dt, g Ntionl AIDS Control Orgniztion. Prtnering with NGOs. New Delhi: NACO; Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10) A

11 Reserch Lorn Guinness et l. Tle 2. Assumptions mde in the sensitivity nlysis to ccount for dt limittions Input Bseline ssumption Prolem Vlue(s) used in Source sensitivity nlysis No. of trining Numer of sessions sed Dt incomplete t Funding gency-specific Funding gency ccounts sessions on dt from NGOs mny NGOs stndrdized quntity nd cost Eductionl Mterils on site or recorded s Dt incomplete t Funding gency-specific Designer nd supplier of mterils distriuted; ssumption sed mny NGOs; mterils stndrdized quntity nd cost eductionl mterils on oservtionl tour, interviews worn out or not nd records of distriution ville Condoms sold Revenue from condoms = cost No records ville; No revenue from condom sles Not pplicle of condoms purchsed y NGO mny NGOs not selling condoms tht re procured for sles Personnel Project director s own estimtion Inccurcies in self- Interqurtile rnge of vlue of Smple of project director s of their own verge income reported dt nd project director s income reported income missing dt Peer eductors For ech NGO: {medin vlue Inccurcies in self- Minimum nd mximum Interviews with peer of time} x {medin time spent on reported dt nd vlues of time cost eductors nd South Indi project ctivities}; sed on missing dt humn development report interviews with peer eductors NGOs = nongovernmentl orgniztions. Ntionl Council of Applied Economic Reserch. South Indi humn development report. New Delhi: Oxford University Press; B Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10)

12 Lorn Guinness et l. Reserch Appendix 1. Clssifiction nd sources of fixed nd vrile costs Ctegory Item Source Fixed costs All gency level costs (including trining Agency slry nd expenditure records nd eductionl mterils) Building nd/or office rent nd running expenses Expenditure records; oservtionl tour; locl mrket prices Equipment nd vehicles Expenditure records; oservtionl tour; locl mrket prices Trining Trining nd expenditure records Monitoring Expenditure records Intervention personnel (project director, project mnger, Slry records; interviews with individul stff dministrtive nd other support stff) Vrile costs Intervention personnel (outrech stff) Slry records; interviews with individul stff Peer eductors Interviews with peer eductors; vlues cross-checked for crediility with outrech stff Condoms Condom distriution records; locl mrket prices Eductionl mterils Oservtionl tour; informtion mteril distriution records; locl printing prices STI tretment costs Where orgniztion hs own clinic: physicin interviews; drug records; locl mrket prices Where dt ville on symptoms treted: STI symptom records; Syndromic cse mngement guidelines; locl mrket prices Where dt on symptoms treted not ville: STI prevlence survey;, c Syndromic cse mngement guidelines; locl mrket prices Meetings Meeting records; expenditure records Trnsport Expenditure records Informtion on ptient referrls nd tretment susides used. Source: Syndromic cse mngement guidelines. New Delhi: Ntionl AIDS Control Orgnistion; Undted. c Bhuyn K, Shorni T, Venkteswr Ro K. Prevlence of sexully trnsmitted infections nd HIV mong femle sex workers of Kkind nd Peddpurm, Andhr Prdesh, Indi. Hyderd: Andhr Prdesh Stte AIDS Society, CHANGES, Fmily Helth Interntionl, Deprtment for Interntionl Development; Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10) C

13 Reserch Lorn Guinness et l. Appendix 2. Medin tests of reltionship etween unit cost nd context (stte), finncing mechnism (funding gency), cpcity (whether certified to receive foreign funds) nd production technology (service provision) Vrile Sttistic Stte Funding gency Certified to receive Service provision foreign funds for STIs Tmil Andhr B C D A Yes No Yes No Ndu Prdesh (n = 2) (n = 2) (n = 4) (n = 9) (n = 14) (n = 3) (n = 2) (n = 15) (n = 8) (n = 11) Coverge Medin (n = 15) Rnge ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) χ² STIs Medin referred Rnge ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) (4, ) ( ) (n = 17) χ² STIs Medin NA treted Rnge ( ) ( ) (n = 1) ( ) ( ) ( ) (n = 1) ( ) ( ) (n = 14) χ² Condoms Medin distriuted Rnge (2 54) (3 45) (12 15) (2 4) (9 54) (3 45) (2 54) (4 15) (12 33) (2 54) (n = 17) χ² First contct Medin NA with trget Rnge ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) ( ) group χ² (n = 15) All contcts Medin NA with trget Rnge ( ) (73 406) ( ) (73 474) (73 406) ( ) ( ) (73 474) group χ² (n = 11) All contcts Medin NA with Rnge ( ) (66 356) ( ) (4 356) (66 356) ( ) ( ) (66 356) community χ² (n = 11) STIs = sexully trnsmitted infections. NA = not pplicle D Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10)

14 Lorn Guinness et l. Reserch Appendix 3. Spermn rnk order tests of unit costs nd finncing (udget), progrmme mturity (project ge), size of nongovernmentl orgniztion (expenditure nd percentge of stff working on HIV project), context in which intervention tkes plce (litercy rte) nd personnel costs Reltionship etween cost per unit of scle nd intervention chrcteristic (r s) Intervention Budget Project Expendi- % stff Litercy Project Project Outrech Adminis- Peer chrcteristic ge ture working rte director s mnger s worker s trtive eductor s on HIV verge verge verge stff verge income income cost verge cost Scle cost Coverge Sexully trnsmitted infections referred Sexully trnsmitted infections treted Condoms distriuted First contct with trget group All contcts with trget group All contcts with community P < P < 0.01 Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10) E

15 Reserch Lorn Guinness et l. Sttisticl tle for Fig. 1 Chrcteristic Regression n F Adjusted R² Coefficient on Coefficient on squred Constnt scle vrile scle vrile Sex workers reched Liner Qudrtic Sexully trnsmitted Liner infections referred Qudrtic Sexully trnsmitted Liner infections treted Qudrtic Condoms distriuted Liner Qudrtic Trget group first Liner contcts Qudrtic Trget group ll Liner contcts Qudrtic All contcts Liner Qudrtic P < P < 0.01 Sttisticl tle for Fig. 2 Chrcteristic Regression Numer of F Adjusted R² Coefficient on Coefficient on Constnt oservtions scle vrile squred scle vrile Sex workers reched Liner Qudrtic Sexully trnsmitted Liner infections referred Qudrtic Sexully trnsmitted Liner infections treted Qudrtic Condoms distriuted Liner Qudrtic Trget group first Liner contcts Qudrtic Trget group ll Liner contcts Qudrtic All contcts Liner Qudrtic P < P < 0.01 Sttisticl tle for Fig. 3 Regression model F Adjusted R² Coefficient on Coefficient on squred Constnt scle vrile scle vrile Totl costs Using mximum cost vlues Using minimum cost vlues Cost per sex worker reched Using mximum cost vlues Using minimum cost vlues P < P < 0.01 F Bulletin of the World Helth Orgniztion Octoer 2005, 83 (10)