A population-based study of the incidence and outcomes of diagnosed chronic kidney disease

Background This study aims to determine the incidence rate and prognosis of detected chronic kidney disease (CKD) in a defined population. Methods: This is a retrospective cohort study of all new cases of CKD from Southampton and South-West Hampshire Health Authority (population base, 405,000) determined by a persistently increased serum creatinine (SCr) level (greater than or equal to1.7 mg/dL [greater than or equal to150 mumol/L] for 6 months) identified from chemical pathology records. Follow-up was for a mean of 5.5 years for survival, cause of death, and acceptance to renal replacement therapy (RRT). Results The annual incidence rate of detected CKD was 1,701 per million population (pmp; 95% confidence interval [CI], 1,613 to 1,793) and 1,071 pmp (95% Cl, 1,001 to 1,147) in those younger than 80 years. There was a steep age gradient; median age was 77 years. The man-woman rate ratio was 1.6 (95% Cl, 1.4 to 1.8), with a male excess in all age groups older than 40 years. Incidence increased in areas with greater socioeconomic deprivation. Median survival was 35 months. Age, SCr level, and deprivation index were all significantly associated with survival. Standardized mortality ratios were 36-fold in those aged 16 to 49 years, 12-fold in those aged 50 to 64 years, and more than 2-fold in those older than 65 years. Cardiovascular disease (CVD) was the most common cause of death (46%). Only 4% of patients were accepted to RRT. Conclusion: The incidence of diagnosed CKD is common, especially in the elderly, and is greater in more deprived areas. Prognosis is poor, with CVD prominent. More research is needed to assess the effectiveness and costs of increasing referral to nephrologists of patients with CKD.