Assessing disability-adjusted life years (DALY) from multiple medication use and multiple illnesses of older adults in rural Thailand.

backgroundGeriatric syndromes including polypharmacy and multimorbidity represent growing public health challenges in aging rural populations, yet their population-level burden remains poorly quantified in low- and middle-income countries.

objectiveThis study aimed to quantify gross disease burden, expressed as disability-adjusted life years (DALYs), across 25 conditions in a large rural Thai older adult population. Particular emphasis was placed on polypharmacy, multimorbidity, and potentially inappropriate medications, alongside the identification of disease clustering patterns to inform integrated care planning.

methodsPopulation-based cross-sectional study of 587,905 older adults (aged ≥ 60 years) from 46 secondary hospitals in the 8th Health Service Region of northeastern Thailand. DALYs were calculated using Global Burden of Disease 2017 methodology. Polypharmacy was defined as concurrent use of ≥ 5 unique active pharmaceutical ingredients (APIs) for ≥ 90 consecutive days, assessed over both 2-year and 3-year lookback windows. Multimorbidity was defined as ≥ 2 chronic conditions. Potentially inappropriate medications were assessed using 2019 American Geriatrics Society Beers Criteria and Thai Rational Drug Use (RDU) criteria. DALY estimates represent gross population-level burden attributable to each condition or syndrome, without adjustment for co-occurring conditions.

resultsTotal disease burden was 48.4 million DALYs (8,240,612 DALYs per 100,000 population). Diabetes mellitus accounted for the highest burden (16,511,859 DALYs; 2,910,112 per 100,000), followed by hypertension (8,331,200 DALYs; 1,417,720 per 100,000). Polypharmacy affected 59.5% (n = 349,803) contributing 4,035,612 DALYs (686,408 per 100,000), with YLL comprising 54.3% of this burden. Multimorbidity affected 48.6% (n = 285,721) contributing 3,301,572 DALYs. Potentially inappropriate medications were present in 32.1% (n = 188,718). The most common disease clusters were diabetes, hypertension, renal failure and respiratorycardiovascular combinations.

conclusionsPolypharmacy and multimorbidity represent substantial gross population-level burdens in rural Thai older adults. These findings apply specifically to older adults accessing outpatient services at secondary hospitals in the 8th Health Service Region and should not be generalized to the entire rural older adult population. High prevalence of potentially inappropriate medications indicates urgent need for medication optimization interventions. Diabetes emerges as the leading disease burden despite lower prevalence than hypertension, highlighting the importance of DALY-based priority setting. These gross DALY estimates should be interpreted as descriptive measures of population health loss associated with each condition, rather than causal or adjusted effect estimates.