Comparison of phenotypes of polycystic kidney disease types 1 and 2

Background Although autosomal dominant polycystic kidney disease type 2 (PK D2) is known to have a milder clinical phenotype than PKD1, neither disorde r has been compared with an unaffected control population in terms of survi val. We report the findings;of a multicentre survey that aimed to define mo re precisely;Phe survival and clinical expression of PKD1 and PKD2. Methods Clinical data from 333 people with PKD1 (31 families) were compared with data from 291 people with PKD2(31 families) and 398 geographically ma tched controls. Survival analysis was used to compare age-at-event data. Di fferences in the prevalence of complications were assessed by logistic regr ession. Findings Median age at death or onset of end-stage renal disease, was 53.0 years (95% CI 51.2-54.8) in individuals with PKD1, 69.1 years (66.9-71.3) i n those with PKD2, and 78.0 years (73.8-82.2) in controls. Women with PKD2 had a significantly longer median survival than men (71.0 [67.4-74.8] vs 67 .3 [64.9-69.7] years), but no sex influence was apparent in PKD1. Age at pr esentation with kidney failure was later in PKD2 than in PKD1 (median age 7 4.0 [67.2-80.8] vs 54.3 [52.7-55.9] years). PKD2 patients were less likely to have hypertension (odds ratio 0.25 [95% CI 0.15-0.42]), a history of uri nary-tract infection (0.50 [0.31-0.83]), or haematuria (0.59 [0.35-0.98]). Interpretation Although PKD2 is clinically milder than PKD1, it has a delet erious impact on overall life expectancy and cannot be regarded as a benign disorder.