Comorbidity of mental and physical conditions in the Hong Kong general population: a latent class approach

Abstract

OBJECTIVES: Co-occurrence of mental and physical conditions has been recognised for its impact on functional disability. The present study aimed to examine the interrelationships among 9 mental problems and 7 physical conditions, also the factor and impact of comorbidity. METHODS: Hong Kong Mental Morbidity Survey (HKMMS) is the first community-based epidemiological mental health study in Hong Kong. Overall, 5,719 adult population aged 16 to 75 years were recruited from November 2010 to May 2013. Latent class analysis (LCA) with dichotomous division was employed to determine the comorbidity pattern. Mental conditions targeted for the analysis included common mental disorders, psychotic disorder, and alcohol and substance abuse. Physical component consisted of conditions from the following categories: cardiovascular, respiratory, gastrointestinal, genitourinary, musculoskeletal, neurological, and endocrine-metabolic. The LCA analysis was conducted using Mplus 7.0 (Muthén & Muthén, 2012). Model fit was assessed using statistical indices: likelihood ratio chi-squared (LRχ2), Akaike information criterion (AIC), Bayesian information criterion (BIC), sample-size adjusted BIC (SSABIC), Lo-Mendell-Rubin–adjusted LR test (LRT), and entropy measures. Each participant was assigned to the latent class with the largest posterior probability. Factors associated with each class were examined by logistic regression analysis. RESULTS: A total of 5,595 participants who had completed data were included in the LCA. A 3-class model was suggested with smaller values of AIC and SSABIC, and significant change difference in LRT. Class I (unaffected, 90.7% of sample) had markedly high proportions of individuals who reported with absent or very low probability in both conditions. Class II (multiplex, 4.9% of sample) participants had reported large percentages of multiple mental and physical conditions, with the poorest outcome in functioning. Class III (mixed, 4.5% of sample) identified a largest proportion of mixed anxiety and depressive disorder. CONCLUSIONS: The finding offers important understanding on the complex patterns of comorbidity among Hong Kong general population.