Interaction effect of psoriasis and chronic kidney disease on the risk of all-cause mortality: a prospective cohort study of NHANES data
Jian Lu, Han Li, Shixiang Wang
Abstract
BACKGROUND: The association between psoriasis, chronic kidney disease (CKD) and mortality remains unclear. This study aimed to examine the combined impact of psoriasis and CKD on mortality in a representative sample of US adults. METHODS: The data for this analysis came from 13 208 participants of the National Health and Nutrition Examination Survey conducted between 2003-06 and 2009-14. Psoriasis was determined through self-reported questionnaire data, while CKD was defined as an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2 or urinary albumin to creatinine ratio (UACR) ≥30 mg/g. A four-level variable was created using the information on psoriasis and CKD, and survival probability was estimated using the Kaplan-Meier method. The survival analysis was conducted using weighted Cox proportional hazards regression models. RESULTS: In a 9.83-year average follow-up period, 539 deaths occurred, with a prevalence of psoriasis in CKD at 2.94% and an all-cause mortality rate of 33.30%. In the multivariable analyses, individuals with both psoriasis and CKD had hazard ratios (HRs) of 5.38 (95% CI 2.43-11.91) for all-cause mortality compared with those with neither psoriasis nor CKD. Participants with both psoriasis and low eGFR had an HR of 6.40 (95% CI 2.01-20.42), while those with both psoriasis and albuminuria had an HR of 5.30 (95% CI 2.24-12.52). A significant interaction between psoriasis, CKD and all-cause mortality was found in the fully adjusted model (P = .026), and a significant synergistic effect between psoriasis and albuminuria was discovered (P = .002). However, the interaction effects between psoriasis, low eGFR and all-cause mortality were only observed in the unadjusted model (P = .036). CONCLUSIONS: Screening for psoriasis in individuals at risk for developing CKD may help in risk stratification for all-cause mortality related to psoriasis. The assessment of UACR may be useful in identifying psoriasis at increased risk for all-cause mortality.