Association of multimorbidity and its patterns with incident possible sarcopenia among middle-aged and older adults: findings from a national prospective cohort study in China

Associations between multimorbidity and patterns with incident possible sarcopenia (PSA) risk have been inconclusive. This longitudinal study aimed to assess the associations between multimorbidity, multimorbidity patterns and new-onset PSA in middle-aged and older adults. A total of 4814 individuals from the China Health and Retirement Longitudinal Study (CHARLS) were included. PSA was defined according to the Asian Working Group for Sarcopenia 2019 criteria. Latent class analysis was employed to identify multimorbidity patterns from 14 chronic diseases. Cox proportional hazards regression models were used to evaluate the effect of multimorbidity and comorbidity patterns on PSA. During a mean follow-up of 3.4 (SD, 0.9) years, 1299 (27.0%) participants developed PSA. Participants with multimorbidity (HR: 1.23, 95% CI: 1.09–1.38, p < 0.001) were more likely to develop PSA. Four patterns, namely relatively healthy pattern, cardiometabolic pattern, digestive-arthritis pattern, and respiratory pattern were identified. Participants with digestive-arthritis pattern (HR, 95% CI: 1.25, 1.04–1.49, p = 0.014) and respiratory pattern (HR, 95% CI: 1.48, 1.15–1.90, p = 0.002) had a greater risk of incident PSA compared to those with the relatively healthy pattern. A significant positive relationship between multimorbidity and PSA risk was found among adults aged 45–59 in the age-stratified analysis (HR = 1.27, 95% CI: 1.07–1.50, p = 0.006). The respiratory pattern and digestive-arthritis pattern significantly increased the risk of developing PSA among female adults or individuals aged less than 70. Multimorbidity was associated with an increased risk of new-onset PSA among middle-aged and older adults, with population-specific differences by age and sex. A significant positive association was observed between multimorbidity and incident PSA risk in adults aged 45–59 years, The respiratory disease pattern and digestive-arthritis disease pattern significantly elevated PSA risk in female as well as in adults aged < 70 years. Conducting public health programs aimed at maintaining a healthy multimorbidity profile, preventing multimorbidity, and intervening in the digestive-arthritis and respiratory disease patterns is essential for reducing the risk of developing PSA among middle-aged and older adults.