Beyond the Norm: Exploring Multimorbidity Risks with Random Survival Forest in India's Aging Demographic

Abstract India is passing through a parallel phase of demographic and epidemiological transition with the double burden of Non-communicable Diseases (NCDs) and Communicable Diseases (CDs). Unhealthy ageing has been identified as the primary driver of the multimorbidity and morbidity burden among older adults in India. This study aims to assess the relative proportional share of morbidities and multimorbidity counts, estimate multimorbidity risk for socioeconomic and demographic factors and further evaluate multimorbidity counts risk conditioned on leading factors. The study used the data from Longitudinal Ageing Study in India (LASI), Wave – 1, 2017–18, aged 45 years and above. First, we assessed the relative proportional share of morbidities and multimorbidity over age using the stacked graph. Further, we applied the Random Survival Forest (RSF) model to estimate the risk of multimorbidity associated with socioeconomic and demographic factors over age. Further, conditional plots were utilised to assess the distribution of leading factors on multimorbidity counts. The prevalence of multimorbidity was 43.20%. Eye disorders, followed by CVDs, had the highest proportional share over age. Endocrine diseases, Gastrointestinal Conditions and Infectious diseases showed a concordant decreasing proportional share in the ageing population. The relative proportion of five or more multimorbidity increased significantly with age. The median expected risk of multimorbidity in females (66 years) was significantly higher than in males (71 years). The study also provides empirical evidence that individuals with higher levels of education, obesity, who are currently working, and who had poor childhood health were more prone to higher risk of multimorbidity at an early age. Further, obesity was significantly associated with early multimorbidity onset and led to a pronounced escalation of complex multimorbidity, particularly in females. Targeted public health interventions are crucial to address diseases early onset and burden disparities to promote healthier aging among older adults in India