BACKGROUND: Psoriasis is a chronic inflammatory skin disease that affects quality of life, but its relation to suicide is uncertain. Objectives: The aim of this study was to evaluate the risk of suicide, suicidal behavior, and mortality in patients with psoriasis compared with patients without psoriasis.
METHODS: The study used data from the Clinical Practice Research Datalink (CPRD) from practices linked to Hospital Episode Statistics (HES) data and Office for National Statistics (ONS) mortality data from 2000 through 2013. Patients ≥ 18 years of age were eligible for inclusion in the psoriasis (PSO) cohort at the first occurrence of a psoriasis diagnosis recorded in CPRD (index date) after a minimum of 12 months registration in an up-to-standard practice. A comparator cohort (NonPSO) without a PSO diagnosis before the index date was formed by matching up to 5 patients for each PSO patient on general practice, age group, and sex. Propensity scores were developed based on history of medical conditions and medication use, health care utilization, and the three matching variables. Propensity scores were used to trim the cohorts and then stratify them based on the decile cut points of the PSO cohort. Suicide, suicidal behavior, and death were identified through Read codes and ICD-10 codes in CPRD, HES, and ONS data. Incidence rates (IR), IR ratios (IRR) and 95% confidence intervals (CI) were calculated for PSO versus NonPSO cohorts, standardized by propensity score decile.
RESULTS: The PSO cohort comprised 44,999 patients followed for 235,773 person-years (py). The NonPSO cohort comprised 222,836 patients followed for 1,068,639 py. Standardized IRs (95% CI) for suicide per 100,000 py were PSO: 7.6 (4.5-12.1), NonPSO: 12.5 (10.3-15.0); for suicide or suicidal behavior per 10,000 py were PSO: 19.7 (18.0-21.6), NonPSO: 18.5 (17.6-19.5); and for mortality per 1,000 py were PSO: 9.4 (9.0-9.8), NonPSO: 10.5 (10.3-10.7). The standardized IRR (95% CI) of PSO to NonPSO for suicide was 0.61 (0.37-1.00); for suicide/suicidal behavior, 1.06 (0.96-1.18); and for mortality, 0.90 (0.86-0.94).
CONCLUSIONS: Risks of suicide or suicidal behavior, completed suicide, and total mortality were similar for the PSO and NonPSO cohorts, with only small differences that were consistent with random variability.
