Mortality Among Danish Patients with a Hospital Diagnosis of Overweight or Obesity Over a 40-Year Period

Purpose: Data on long-term mortality among patients with hospital-diagnosed overweight/obesity are limited. Thus, we aim to examine 40-year mortality among patients with hospital-diagnosed overweight/obesity, including cause-specific deaths, secular time trends, and potential effect modification by age, comorbidity, and socioeconomic factors. Patients and Methods: From national registries, we identified all Danes with a first hospital-based overweight/obesity diagnosis (N=331,185), 1979-2018, and constructed an age-and gender-matched general population comparison cohort (N=1,655,925). We computed mortality rates (MRs) per 1000 person-years and adjusted mortality rate ratios (aMRRs) with 95% confidence intervals (CIs), using Cox regression with adjustment for comorbidities and educational level. We performed stratified analyses on age, comorbidities, and socioeconomic factors. Results: The overall aMRR was 1.70 (95% CI: 1.68-1.72) for patients with overweight/obesity, mainly due to diabetes and other endocrine diseases (aMRR=2.68 [95% CI: 2.57-2.81]), cardiovascular (aMRR=1.95 [95% CI: 1.91-1.98]), and respiratory diseases (aMRR=1.83 [95% CI: 1.77-1.89]). The 1-10-year aMRR decreased from 2.06 (95% CI: 2.01-2.11) in 1979-1989 to 1.29 (95% CI: 1.26-1.32) in 2000-2009. We found effect modification by age: age 18 to <30 years: aMRR=2.44 (95% CI: 2.24-2.66) vs age >= 70 years: 1.35 (95% CI: 1.33-1.37); comorbidities: baseline comorbidities: aMRR=1.13 (95% CI: 1.10-1.15) vs no comorbidities: aMRR=1.83 (95% CI: 1.80-1.85); and educational level: high educational level: aMRR=1.81 (95% CI: 1.74-1.88) vs low educational level: aMRR=1.70 (95% CI: 1.67-1.72). Conclusion: Patients with overweight/obesity had a substantially increased long-term mortality, mainly due to diabetes, cardiovascular, and respiratory diseases. The excess mortality decreased during recent decades. Age, comorbidities, and socioeconomic factors modified the association.