Kidney disease in moderate-to-severe psoriasis: a critical appraisal.

Abstract

Using a population-based cohort, Wan etal. examined the risk of moderate-to-advanced (stage 3-5) chronic kidney disease (CKD) in patients with psoriasis. A population-based cohort was constructed using The Health Improvement Network (THIN) database. THIN is an electronic primary healthcare records database containing routinely collected medical diagnosis and drug prescribing data on >9million patients in the U.K. Data were collected prospectively on 143883 adults (aged 18-90years) with psoriasis. Of these, 7354 had severe psoriasis, as defined by prescription codes for systemic medication or treatment codes for phototherapy. Patients with psoriasis were matched with up to five nonpsoriasis age- and practice-matched controls. Patients with a diagnosis of CKD before study entry were excluded. In addition, baseline data from the Incident Health Outcomes and Psoriasis Events (iHOPE) study, a cohort of 8731 primary care patients aged 25-64years with psoriasis, was included. Psoriasis severity was categorized according to body surface area (BSA) involvement as estimated by general practitioners. A similar method using a patient-reported BSA assessment tool was previously validated by the same group. Patients were matched by age and practice with 10 nonpsoriasis controls. Psoriasis, identified on the basis of a recorded diagnostic code for psoriasis. Incident CKD was defined as the presence of a recorded diagnostic code consistent with moderate-to-advanced (stage 3-5) CKD or laboratory parameters consistent with the diagnosis (estimated glomerular filtration rate <60mLmin(-1) 1·73m(-2) ) during follow-up. Prevalent CKD (as defined above) in the cross-sectional data from the iHOPE study. The adjusted hazard ratios for incident CKD were 1·05 [95% confidence interval (CI) 1·02-1·07], 0·99 (95% CI 0·97-1·02) and 1·93 (95% CI 1·79-2·08) in the overall, mild and severe psoriasis groups, respectively. In the nested cross-sectional study (iHOPE) the adjusted prevalence odds ratios for CKD were 0·89 (95% CI 0·72-1·10), 1·36 (95% CI 1·06-1·74) and 1·58 (95% CI 1·07-2·34) in the mild, moderate and severe psoriasis groups, respectively. Moderate-to-severe psoriasis is associated with an increased risk of moderate-to-advanced CKD, independently of traditional risk factors.