Supplementary Online Content Pham B, Stern A, Chen W, et al. Preventing pressure ulcers in long-term care: a costeffectiveness analysis. Arch Intern Med. Published online September 26, 2011. doi:10.1001/archinternmed.2011.473 eappendix. emethods etable 1. Characteristic of the population-based cohort of LTC residents from the Resident-Assessment Instrument Minimum Data Set etable 2. Pressure ulcer risk, prognosis and costs efigure. A natural history model of pressure ulcers among long-term care residents This supplementary material has been provided by the authors to give readers additional information about their work.
eappendix: emethods Pressure ulcer prognosis We estimated the eight transition rates across pressure ulcer stages in efigure 1 using an analytical procedure by Berlowitz et al. 2001. 1, 2 Each resident-specific Resident Assessment Instrument Minimum Data Set (RAI-MDS) assessment was used as a new baseline for the following assessment, if available. For example, the first quarterly assessment provided follow-up data for the admission assessment, and acted as the baseline for the next quarterly assessment. The quarterly incidence of developing pressure ulcers was estimated by the number of residents with stage 1 pressure ulcer(s) at the follow-up assessment among residents who were without pressure ulcers at baseline. The quarterly transition rate from stage 1 to 2 was estimated by the number of residents with stage 2 pressure ulcers at the follow-up assessment among residents who exhibited stage 1 pressure ulcers at baseline. This algorithm was repeated for all pressure ulcer stage transitions. Cost inputs Most of the health care needs of Ontario LTC residents are publicly covered. The RAI-MDS cohort was linked to administrative databases characterizing hospitalization (Canadian Institute of Health Information - Discharge Abstract Database), physician services and diagnostic tests (Ontario Health Insurance Plan database), and ambulatory and emergency care (National Ambulatory Care Reporting System). 3 Summary data of monthly health services used within ±15 days of each RAI-MDS assessment date were obtained and weekly costs derived (etable 2). 4 References 1. Berlowitz DR, Brandeis GH, Morris JN, et al. Deriving a risk-adjustment model for pressure ulcer development using the Minimum Data Set. J Am Geriatr Soc. Jul 2001;49(7):866-871. 2. Berlowitz DR, Brandeis GH, Anderson JJ, et al. Evaluation of a risk-adjustment model for pressure ulcer development using the Minimum Data Set. J Am Geriatr Soc. Jul 2001;49(7):872-876. 3. Canadian Institute of Health Information. Quality assurance processes applied to the discharge abstract and hospital morbidity databases. Ottawa: Canadian Institute of Health Information;2008. 4. Toronto Health Economics and Technology Assessment (THETA) Collaborative. Cost Effectiveness of Prevention Strategies for Pressure Ulcers in Long-Term Care: Projection from the Ontario Pressure Ulcer Model: THETA Ontario Pressure Ulcer Team and the Medical Advisory Secretariat, Ontario Ministry of Health and Long-Term Care;2008. 5. Friedman R, Kalant N. Comparison of long-term care in an acute care institution and in a long-term care institution. Cmaj. 1998;159(9):1107-1113.
etable 1. Characteristic of the population-based cohort of LTC residents from the Resident-Assessment Instrument Minimum Data Set Characteristics (n=18,325 residents) Estimate Standard error Source Mean age (years) 83.6 10.7 RAI-MDS Female (%) 69.3 4.2 RAI-MDS Risk factors Impaired mobility while in bed * (%) 44.1 4.5 RAI-MDS Recent weight loss (%) 19.7 3.7 RAI-MDS Bladder or bowel incontinence (%) 65.3 4.3 RAI-MDS 3-month incidence of stage 2 pressure ulcers (%) 2.61 0.07 RAI-MDS Notes: The RAI-MDS cohort included 89 LTC facilities and 18,325 residents. RAI-MDS data were from May 2004 to November 2007. * RAI-MDS item G1aa=3, 4, 8. RAI-MDS item K3a=1. RAI-MDS item H1ab=2, 3, 4. Value is standard deviation instead of standard error for other estimates.
etable 2. Pressure ulcer risk, prognosis and costs Base case Standard error or Distribution Reference # or Pressure ulcer risk and prognosis Range Source Risk-adjustment scale* 2 Low risk of developing pressure ulcers (%) 36.8 4.4 Beta RAI-MDS Transition rates among low-risk residents Weekly incidence of stage 1 pressure ulcers (%) 0.32 0.20, 0.39 Age-specific RAI-MDS Weekly transition rate from stage 1 to 2 (%) 1.35 0.89, 1.63 Age-specific RAI-MDS Weekly transition rate from stage 2 to 3 (%) 0.05 0.02, 0.13 Age-specific RAI-MDS Weekly transition rate from stage 3 to 4 (%) 0.28 0.08, 0.48 Age-specific RAI-MDS Weekly healing rate for stage 1 (%) 29.74 15.05, 38.68 Age-specific RAI-MDS Weekly healing rate for stage 2 (%) 2.44 0.67, 2.81 Age-specific RAI-MDS Weekly healing rate for stage 3 (%) 1.49 0.28, 2.27 Age-specific RAI-MDS Weekly healing rate for stage 4 (%) 0.41 0.15, 1.01 Age-specific RAI-MDS Hospitalization and mortality Weekly hospitalization rate among low-risk residents # (%) 1.24 0.32 Age-specific CIHI-DAD Inpatient mortality among hospitalized low-risk residents # (%) 4.57 1.75 Age-specific CIHI-DAD Annual mortality in LTC among low-risk residents # (%) 13.49 3.47 Age-specific RAI-MDS
etable 2. Pressure ulcer risk, prognosis and costs Base case Standard error or Range Distribution Reference # or Source Average hospitalization cost $6,924 $3,634 SD Gamma CIHI-DAD Average cost of medications per resident per week $6.16 Not varied 5 Average cost of laboratory tests per resident per week $1.61 Not varied 5 Average cost of X-rays per resident per week $0.98 Not varied 5 Average physician cost per resident per week Low-risk Pressure ulcer stage 0-1 $3.64 Not varied OHIP Low-risk Pressure ulcer stage 2 $8.19 Not varied OHIP Low-risk Pressure ulcer stage 3 4 $7.98 Not varied OHIP High-risk Pressure ulcer stage 0-1 $4.69 Not varied OHIP High-risk Pressure ulcer stage 2 $8.54 Not varied OHIP High-risk Pressure ulcer stage 3-4 $7.14 Not varied OHIP Average Emergency Room visit cost per resident per week Low-risk Pressure ulcer stage 0-1 $5.81 Not varied NACRS Low-risk Pressure ulcer stage 2 $15.96 Not varied NACRS Low-risk Pressure ulcer stage 3 4 $12.60 Not varied NACRS High-risk Pressure ulcer stage 0-1 $9.80 Not varied NACRS High-risk Pressure ulcer stage 2 $10.01 Not varied NACRS High-risk Pressure ulcer stage 3-4 $13.44 Not varied NACRS Abbreviations: RAI-MDS: Resident Assessment Instrument - Minimum Data Set. CIHI-DAD: Canadian Institute of Health Information - Discharge Abstract Database. OHIP: Ontario Health Insurance Plan. NACRS: National Ambulatory Care Reporting System. Notes: * Based upon 17 RAI-MDS items. # Events were unrelated to pressure ulcers. Cost per resident per week for all residents regardless of pressure ulcer risk or pressure ulcer stages.
efigure: A natural history model of pressure ulcers among long-term care residents Local Infection Local / Systemic Infection High Risk for PrU No PrU* Chronic PrU 1 Chronic PrU 2 Chronic PrU 3 Healable PrU 1 Healable PrU 2 Healable PrU 3 H 10 H 20 H 30 H 40 Chronic PrU 4 Healable PrU 4 Residents P 01 P 12 P 23 P 34 Low Risk for PrU No PrU* Healable PrU 1 Chronic PrU 1 Healable PrU 2 Chronic PrU 2 Healable PrU 3 Chronic PrU 3 Healable PrU 4 Chronic PrU 4 Local Infection Local / Systemic Infection Notes: PrU: pressure ulcer. No PrU indicates none or healed pressure ulcers. Weekly progression probabilities P 01, P 12, P 23, and P 34 and healing probabilities H 10, H 20, H 30, and H 40 were estimated using data from successive skin assessments in the RAI-MDS cohort.