Estimating the rate of non-participation and its influence on the study results: Sankara Nethralaya Diabetic Retinopathy Epidemiology and Molecular Genetics Study report 32.
PURPOSE: To report the non-participation rates in a cross-sectional study, compare participants with non-participants, elucidate barriers for non-response and evaluate the influence of non-responders on the outcome measure. METHODS: The Sankara Nethralaya.....