Mortality rates in people with first diagnosis of schizophrenia-spectrum disorders: A 5-year population-based cohort study

Objective: Schizophrenia-spectrum disorder (SSD) is associated with increased premature death, with emerging data suggesting early illness course as a high-risk period for excess mortality. This study aimed to examine mortality rate in patients with incident SSD and differential mortality risk between inpatient-diagnosed and outpatient-diagnosed subsamples within 5 years of first diagnosis. Method: This population-based cohort study identified 8826 patients aged 18-39 years receiving first-recorded SSD diagnosis upon service entry, comprising 3877 inpatient-diagnosed and 4949 outpatient-diagnosed patients, between 2006 and 2012 in Hong Kong using a territory-wide medical record database of public health care services. All-cause, natural-cause, and unnatural-cause mortality risks within 5 years after first diagnosis were quantified by standardized mortality ratios (SMRs) relative to the general population. We also directly compared mortality rates between inpatient and outpatient subsamples over 5-year follow-up. Results: SSD patients exhibited markedly elevated all-cause (SMR: 12.28, 95% confidence interval [CI]: [10.83, 13.88]), natural-cause (SMR: 3.76, 95% CI: [2.77, 4.98]) and unnatural-cause (SMR: 20.64, 95% CI: [17.49, 24.20]) mortality during first 5 years of diagnosis. Increased mortality rate was most pronounced in the first year of treatment, especially for unnatural deaths (SMR 32.2, 95% CI: [24.08, 42.22]). Discharged inpatient-diagnosed patients displayed significantly higher all-cause and unnatural-cause mortality rates than outpatient-diagnosed counterparts within first 3 years of treatment, and differential mortality risks on all-cause (adjusted hazard ratio [aHR]: 7.05, 95% CI: [2.02, 24.64]) and unnatural-cause (aHR: 5.15, 95% CI: [1.38, 19.19]) deaths were the highest in the first month of follow-up. Conclusions: Substantial increase in early mortality risk among people with incident SSD, particularly in the first year of diagnosis and the time shortly after discharge, underscores an urgent need of targeted early intervention for effective suicide prevention and physical health improvement to minimize mortality gap.