Incremental cost-effectiveness of screening and laser treatment for diabetic retinopathy and macular edema in Malawi

Objective To investigate the economic impact of introducing targeted screening and laser photocoagulation treatment for sight-threatening diabetic retinopathy and macular edema in a setting with no previous screening or laser treatment for diabetic retinopathy in sub-Saharan Africa. Materials and methods A cohort Markov model was built to compare combined targeted screening and laser treatment for patients with sight-threatening diabetic retinopathy and macular edema against no intervention. Primary outcomes were incremental cost per quality-adjusted life year (QALY) gained and per disability-adjusted life year (DALY) averted. Primary data were collected on 357 participants from the Malawi Diabetic Retinopathy Study, a prospective, observational cohort study. Multiple scenarios were explored and a probabilistic sensitivity analysis was performed. Results In the base case (age: 50 years, service utilization rate: 80%), the cost of the intervention and the years of severe visual impairment averted per patient screened were $209 and 2.2 years respectively. Applying the World Health Organization threshold of cost-effectiveness for Malawi ($679), the base case was cost-effective when QALYs were used ($400 per QALY gained) but not when DALYs were used ($766 per DALY averted). The intervention was more cost-effective when it targeted younger patients (age: 30 years) and less cost-effective when the utilization rate was lowered to 50%. Conclusions Annual photographic screening of diabetic patients attending medical diabetes clinics in Malawi, with the provision of laser treatment for those with sight-threatening diabetic retinopathy and macular edema, appears to be cost-effective in terms of QALYs gained, in our base case scenario. Cost-effectiveness improves if services are utilized more intensively and extended to younger patients

The period effect in the prevalence of proliferative diabetic retinopathy, gross proteinuria, and peripheral neuropathy in type 1 diabetes: A longitudinal cohort study.

AIMS:To investigate whether, for a specific duration of type 1 diabetes, there is a significant change in the prevalence of proliferative diabetic retinopathy, gross proteinuria and peripheral neuropathy in those more recently diagnosed with diabetes (a period effect), in the Wisconsin Epidemiologic Study of Diabetic Retinopathy. Where present, to determine how common risk factors for diabetic complications might be associated with it, and what might be driving it. MATERIALS AND METHODS:Longitudinal cohort study with seven examination phases between 1980 and 2014. Multivariate logistic regression models and ordinal parameterization were used to test for and evaluate any period effect. RESULTS:There is a period effect in the prevalence of gross proteinuria and peripheral neuropathy (decreasing), as seen with proliferative diabetic retinopathy (p < 0.001). Adjusting for changing levels of common risk factors attenuates the period effect, particularly for proliferative diabetic retinopathy. For gross proteinuria and peripheral neuropathy, however there is a persistent period effect in spite of adjusting for the major risk factors. CONCLUSIONS:There are period effects in the prevalence of proliferative diabetic retinopathy, gross proteinuria and peripheral neuropathy that cannot be fully explained by changes in common risk factors for complications of type 1 diabetes in this cohort. The role of other potential confounders warrants further exploration

Adjusted estimated prevalence of each complication at each study visit.

<p><b>(</b>a) Proliferative diabetic retinopathy–adjusted for duration of diabetes and visit. (b) Proliferative diabetic retinopathy–adjusted for duration of diabetes, visit, glycosylated hemoglobin, and systolic blood pressure. (c) Gross proteinuria—adjusted for duration of diabetes and visit. (d) Gross proteinuria—adjusted for duration of diabetes, visit, glycosylated hemoglobin, mean arterial blood pressure, and sex. (e) Peripheral neuropathy—adjusted for duration of diabetes and visit. (f) Peripheral neuropathy—adjusted for duration of diabetes, visit, glycosylated hemoglobin, sex, and smoking status. Log odds = log [p/(1-p)], i.e. log odds of -0.5 = prevalence of 38%, log odds of -1.0 = prevalence of 27%, log odds of -1.5 = prevalence of 18%, and log odds of -2.0 = prevalence of 12%.</p

Comparison between base and final models of proliferative diabetic retinopathy, gross proteinuria and peripheral neuropathy.

<p>Comparison between base and final models of proliferative diabetic retinopathy, gross proteinuria and peripheral neuropathy.</p

Dates of the WESDR examinations and numbers of participants with type 1 diabetes.

<p>Dates of the WESDR examinations and numbers of participants with type 1 diabetes.</p

Selected characteristics of the all person-visits with the potential to contribute to the primary analyses and all person-visits with complete data for the final models.

<p>Selected characteristics of the all person-visits with the potential to contribute to the primary analyses and all person-visits with complete data for the final models.</p

Model schematic.

<p>The arrows indicate the permitted movement between the health states. NPDR = non-proliferative diabetic retinopathy.</p