Multimorbidity of four cardiometabolic and chronic pulmonary disease groups: prevalence and attributable fraction in US adults, 2007–2012

BACKGROUND: Cardiometabolic and chronic pulmonary diseases may be associated with modifiable risk factors that can be targeted to prevent multimorbidity. OBJECTIVES: (i) Estimate the prevalence of multimorbidity across four cardiometabolic and chronic pulmonary disease groups; (ii) compare the prevalence of multimorbidity to that of one disease and no disease; and (iii) quantify population attributable fractions (PAFs) for modifiable risk factors of multimorbidity. DESIGN: Data from adults aged 18–79 years who participated in the US National Health and Nutrition Examination Survey 2007–2012 were examined. Multimorbidity was defined as ≥2 co-occurring diseases across four common cardiometabolic and chronic pulmonary disease groups. Multivariate-adjusted PAFs for poverty, obesity, smoking, hypertension, and low high-density lipoprotein (HDL) cholesterol were estimated. RESULTS: Among 16,676 adults, the age-standardized prevalence of multimorbidity was 9.3%. The occurrence of multimorbidity was greater with age, from 1.5% to 5.9%, 15.0% and 34.8% for adults aged 18–39, 40–54, 55–64 and 65–79 years, respectively. Multimorbidity was greatest among the poorest versus non-poorest adults and among blacks versus other races/ethnicities. Multimorbidity was also greater in adults with obesity, hypertension, and low HDL cholesterol. Risk factors with greatest PAFs were hypertension (38.8%; 95% confidence interval [CI] 29.4–47.4) and obesity (19.3%; 95% CI 10.2–28.2). CONCLUSIONS: In the USA, 9.3% of adults have multimorbidity across four chronic disease groups, with a disproportionate burden among older, black, and poor adults. Our results suggest that targeting two intermediate modifiable risk factors, hypertension and obesity, might help to reduce the prevalence of multimorbidity in US adults.