Chronic Kidney Disease

Apply modified CALIBER 'Chronic Kidney Disease' algorithm in CPRD primary care data as follows: A patient is defined as having had CKD stage 3 or above at a specified date: IF egfr_ckdepi recorded on or before specified date, THEN IF egfr_ckdepi ⧀60 ml/min on the most recent date (index date) before the specified date AND IF egfr_ckdepi ⧀60 ml/min on any date greater than 90 days BEFORE the index date above THEN classify as having CKD3 or above ELSE the patient is not defined as having CKD stage 3 or above. Where egfr_ckdepi up to and including 31 Dec 2013 is defined as: egfr_ckdepi = 141 * min(crea_gprd * 0.010746 / K, 1)^alpha * max(crea_gprd * 0.010746 / K, 1)^-1.209 * 0.993^age * 1.018 [if female] * 1.159 = [if black] where: alpha = -0.329 for females, -0.411 for males K = 0.7 for females, 0.9 for males Where egfr_ckdepi from and including 1 Jan 2014 is defined as: egfr_ckdepi = 141 * min(crea_gprd *0.011312/ K, 1)^alpha * max(crea_gprd * 0.011312/ K, 1)^-1.209 * 0.993^age * 1.018 [if female] * 1.159 [if black] where: alpha = -0.329 for females, -0.411 for males K = 0.7 for females, 0.9 for males Where crea_gprd is defined as: IF enttype = 165 [Serum creatinine] AND data1 [Operator] = 3 ["="] AND data2 [Value] ⧁ 0 THEN crea_gprd = data2