Wealth related inequalities in self reported morbidity: Positional objectivity or epidemiological transition?

Background & objectives: Morbidity is self reported at a higher rate among the rich than the poor. However, objective measures suggest the contrary. We examined the role of epidemiological transition in wealth related inequalities in self-reported morbidity (SRM). Methods: We analyzed data of two states, Bihar and Kerala, from 60th Round of National Sample Survey (NSS). Bivariate analysis was performed to study the associations between various socio-demographic variables and self-reported morbidity. A prediction model based on hierarchical logistic regression was developed to identify determinants of self-reported morbidity. Results: In Bihar, acute morbidities (26 per 1000) were reported more often than chronic morbidities (19 per 1000) while in Kerala the reverse was true (89 acute and 123 chronic morbidities per 1000 person). In both the states, the rate of SRM showed an increasing trend from the poorest to the richest quintiles. The rising gradient in the odds of SRM across increasing socio-economic strata was more pronounced in Bihar [OR (richest)=2.52; 1.85-3.42] as compared to Kerala [OR (richest) =1.66; 1.37-2.0]. Moreover, this gradient was more on account of chronic diseases [OR (richest) =2.7; 1.8-4.0] for Bihar; [OR (richest) =1.6; 1.26-2.0 for Kerala] than the acute diseases [OR (richest) =1.82; 1.1-2.9 for Bihar]; [OR (richest) =1.4; 1.1-1.8 for Kerala]. Interpretation & conclusions: The present analysis shows that the epidemiologic transition results in higher prevalence and reporting of chronic ailments by the rich than the poor. This phenomenon is more evident in the early stages of transition. In later stages of transition, positional objectivity plays an important role to explain wealth related inequalities in SRM.