The 1 st National TB Prevalence Survey Nigeria 2012 Preliminary/Final Results 29 th April 2013 Dr. Joshua Obasanya NTP Manager/ PI National TB Prevalence Survey
Background Indicator (2011) Population size 162.5million GNI per capita (Atlas method) 2011($1,280) Estimated TB Burden (2011) Number Rate Cases (all forms) 190,000 118/100,000 (2011) Mortality 17 per 100,000 (2011) TB cases with HIV 30% (2011) N/A Case notifications 60 per 100,000 Treatment success 85.5% 2
Methodology
Sampling design Sample size: 49,000 eligible adults (15 yrs and above) Number of clusters: 70 A multi-stage sampling method was used Stratifying the country into 6 geopolitical zone Population based simple random sampling <70> clusters <700> people 4 <49,000> Target
Selection criteria and health seeking behaviour Inclusion criteria All permanent residents in the household Non-permanent residents who have spent at least 2 weeks in the household by the survey day At least 15 years of age Those who have provided informed consent Screening Positive Two sputum samples (1 spot and 1 morning) will be obtained from persons reporting a cough greater than or equal to 2 weeks in duration or chest X- ray examination that show any radiographic abnormalities. Health seeking behaviour (2 questions) What did you do about your symptoms? (Not recognised as illness, ignored, self treatment, consulted health service, others <specify>) If response to question above is consulted health service, Where did you first seek care? (HC/PHC, Private Hosp., Traditional healer, Chemist, GH, Teaching Hosp., Mission Hosp., others <specify>) 5
Laboratory methods Smear: Direct in 2 Labs and Concentrated in 1 Lab Ziehl-Neelsen staining Culture media: Löwenstein Jensen (LJ) For positive growths, identification for MTBC was done Other: 3 Refence Labs were used ( Zankli, NTBLTC Zaria and NIMR) Use of GeneXpert MTB/RIF for few samples with inconsistent results ( specifically for Zaria processed samples) e.g. 1 smear pos sample, cultve, X-ray TB suggestive 6
Main Challenges
Main challenges of survey implementation S/No Challenge Action 1 On-going security challenges in Kano, Kaduna, Yobe and Borno states 2 states (Yobe & Borno) were excluded. To compensate, 3 clusters with similar characteristics were chosen for replacement 2 Low participation due to Rain/Farming/Fasting period 3 Absenteeism experienced in urban settings 4 Backlog and increased workload for Zaria Laboratory ( because 2 clusters ran concurrently) 5 Gaps between field sample collection and lab reporting and between lab reporting and feedback to participants for enrolment of care. These was coupled with sputum transport challenges 6 Delay in Central Xray reading and entry into data base 7 Delayed Procurement (especially lab equipments & consumables availability and specification) which resulted in late take-off of the survey suspension of survey field activities for 5 weeks (from end of July August 26 th 2012) Field teams worked till late hours while re-mobilization was done through community & religious leaders Zankli Lab was engaged to support in processing some of samples already delivered to Zaria Labs were visited routinely every 2 weeks to retrieve results that were delayed Survey central team developed and regularly updated the list of detected cases on weekly basis. Feedbacks of results were sent to patients through State Program officers and Zonal survey coordinators Feedback on enrolment of detected cases received during review meetings Change from public transport to courier transport 5 Additional data clerks were identified to support the central data manager with entry of central X-ray and Lab results. The NTP had to intervene Case review style exercises were consistently carried out with support from WHO 8 Geneva & CDC Atlanta to improve the quality of data generated
RESULTS
Participants Total census 113,057 Eligible to participate 77,596 (68.6%) 34,962 (31%) children 499 (0.44%) non-residents Ineligible individuals Participants 43,439 (56%) 10
Eligibility by age group and sex 100.0 Eligibility by age group and gender Percentage eligible (%) 95.0 Male Female 90.0 11 15 to 24 25 to 34 35 to 44 45 to 54 55 to 64 65+ Age group (years)
Participation by age group and sex Overall participation rate: 56% 100.0 Participation by age group and sex 90.0 Participation rate(%) 80.0 70.0 60.0 Male Female 50.0 40.0 15 to 24 25 to 34 35 to 44 45 to 54 55 to 64 65+ Age Group (Years) 12
Participation by cluster 100 Participation rate by cluster (chronological order) 90 80 70 Participation rate (%) 60 50 40 30 20 10 0 42 56 68 43 54 69 11 70 41 55 44 46 67 47 66 45 14 38 57 49 48 64 39 65 40 50 63 2 51 8 9 13 33 62 1 53 35 3 34 4 61 52 7 18 5 10 6 36 12 60 Cluster number 13
Screening and laboratory investigations Total screened Symptom positive CXR positive Both symptom and CXR positive Screened positive Total specimens obtained Number of participants with lab results 43,439 4,429 (10%) 2,016 (45.5%) 724 (16.4%) 1,670 (38.1%) 4,283 (at least one specimen) 4,283 14
Results of TB Prevalence : Age 15years* 1) Smear Positive MTB case (N=107): 255 per 100,000 (95%CI 178-333) Correlation coefficient of between-cluster variation (k): 0.82 Design effect: 2.56 2) Bacteriologically Confirmed MTB (N=148): 353 per 100,000 (95%CI 264-442) Correlation coefficient of between-cluster variation (k): 0.78 Design effect: 2.48 15
Prevalence of culture confirmed MTB cases by age: 1400 Prevalence of smear-positive and bacteriologically-confirmed TB by age group 1200 Prevalence per 100,000 1000 800 600 400 Smear positive culture positive Bacteriologically positive 200 0 15-24 25-34 35-44 45-54 55-64 65+ Age group (years) 16
Prevalence of culture confirmed smear positive TB by age and sex: 3000 Prevalence of bacteriologically-confirmed TB by sex and age group 2500 Prevalence (per 100,000) 2000 1500 1000 Male Female 500 0 15-24 25-34 35-44 45-54 55-64 65+ Age group (Years) 17 Age Group (Years)
Confirmed MTB survey cases: Symptoms and CXR screening results <Complete this table> Screening method Smear positive MTB survey cases N=107 Bacteriologically confirmed MTB survey cases N=148 Total number of survey cases Percentage of all survey cases Total number of survey cases Percentage of all survey cases Symptom positive only 13 12% 17 11.5% CXR positive only 27 25% 54 36.5% Symptom and CXR positive 67 63% 77 52% What proportion of MTB survey cases were smear negative? 27.7% What proportion of MTB survey cases were detected by CXR? 36.5% What proportion of MTB survey cases were detected by symptoms? 11.5% What proportion of MTB survey cases would have been detected by the current screening strategy in your country? 11.5% 18
Comparison of Prevalence to Notification (2011) 8 Prevalence to Notification Rate ratios; total, by sex, and age group Comparison of notification (2011) to prevalence (smear-positive) 7 Prevalence to Notification ratio 6 5 4 3 2 1 0 National (15+) Male (15+) Female (15+) 15 to 24 yrs Categories 25 to 34 yrs 35 to 44 yrs 45 to 54 55 to 64 65+ yrs yrs yrs 19
Lessons Learnt
Major lessons and implications to the NTP What are the main lessons derived from the survey results? 21 Data management is the bedrock of a successful survey (a simplified and user friendly database is crucial). Low participation rate (56%) 75% of smear positive study cases are symptomatic (consistent with 2013 Prog. Rev. findings) Participation rate higher in females and older individuals ( health seeking behaviour among men still a challenge) Survey findings (prevalence) seems to be higher than current WHO estimates (further analysis required) What action is recommended based on the findings? Modern and strategic approaches to creating awareness within the community is pertinent Strategic expansion of more microscopy centers than DOTS centers to increase access to diagnosis is needed Stakeholders meeting to brainstorm on strategies for increasing case detection
Acknowledgements 22
23 Dedication, mutual responsibility and a sound data management system!
Supplementary slides
Laboratory results Total specimens obtained Any smear positive Any culture MTB S+C+ S-C+ X,XXX (spot) X,XXX (morning) XXX (X.X%) XXX (X.X%) 75(51%) 41 (28%) 25
Study cases Smear positive MTB cases Bacteriologically confirmed MTB cases Total number of study cases 107 148 Definite case 75 39 Probable case 32 2 Possible case 30 Non-study cases 38 - Number of cases that are smear positive - 107 Definite cases: Probable cases: Possible cases: Non-study cases: <Sm pos case, Culture MTB or Xpert Positive> <Sm pos case, No proof of culture or Xpert but CXR consistent with TB> <Sm Pos, Culture not MTB positive ( NA, Neg, Contamination) and CXR not consistent with TB disease> <Possible case including Culture NTM-MOTT> 26
Health seeking behaviour Analysis on-going Indicator Total number of TB survey cases Number of TB survey cases who were not on treatment at the time of the interview Number of TB survey cases who were symptomatic Number of symptomatic TB survey cases not on treatment at the time of the interview Number of TB cases detected by the survey who were already on treatment (Where did they seek care?) Number of symptomatic TB cases not on treatment but who sought care (Where did they seek care?) Number of TB survey cases that started on treatment after being detected by the survey 27