Detecting chronic kidney disease in population-based administrative databases using an algorithm of hospital encounter and physician claim codes

Abstract

BackgroundLarge, population-based administrative healthcare databases can be used to identify patients with chronic kidney disease (CKD) when serum creatinine laboratory results are unavailable. We examined the validity of algorithms that used combined hospital encounter and physician claims database codes for the detection of CKD in Ontario, Canada.MethodsWe accrued 123,499 patients over the age of 65 from 2007 to 2010. All patients had a baseline serum creatinine value to estimate glomerular filtration rate (eGFR). We developed an algorithm of physician claims and hospital encounter codes to search administrative databases for the presence of CKD. We determined the sensitivity, specificity, positive and negative predictive values of this algorithm to detect our primary threshold of CKD, an eGFR <45 mL/min per 1.73 m2 (15.4% of patients). We also assessed serum creatinine and eGFR values in patients with and without CKD codes (algorithm positive and negative, respectively).ResultsOur algorithm required evidence of at least one of eleven CKD codes and 7.7% of patients were algorithm positive. The sensitivity was 32.7% [95% confidence interval: (95% CI): 32.0 to 33.3%]. Sensitivity was lower in women compared to men (25.7 vs. 43.7%; p <0.001) and in the oldest age category (over 80 vs. 66 to 80; 28.4 vs. 37.6 %; p < 0.001). All specificities were over 94%. The positive and negative predictive values were 65.4% (95% CI: 64.4 to 66.3%) and 88.8% (95% CI: 88.6 to 89.0%), respectively. In algorithm positive patients, the median [interquartile range (IQR)] baseline serum creatinine value was 135 μmol/L (106 to 179 μmol/L) compared to 82 μmol/L (69 to 98 μmol/L) for algorithm negative patients. Corresponding eGFR values were 38 mL/min per 1.73 m2 (26 to 51 mL/min per 1.73 m2) vs. 69 mL/min per 1.73 m2 (56 to 82 mL/min per 1.73 m2), respectively.ConclusionsPatients with CKD as identified by our database algorithm had distinctly higher baseline serum creatinine values and lower eGFR values than those without such codes. However, because of limited sensitivity, the prevalence of CKD was underestimated.

Macrolide antibiotics and the risk of ventricular arrhythmia in older adults

“…† †We identified chronic kidney disease using an algorithm of hospital diagnosis codes validated for older adults in Ontario. 52 The presence of codes in this algorithm is associated with a median estimated glomerular filtration rate (eGFR) of 38 (IQR 27-52) mL/min per 1.73 m 2 , whereas an absence of codes is associated with a median eGFR of 69 (IQR 56-82) mL/min per 1.73 m 2 . ‡ ‡Coronary artery disease included receipt of coronary artery bypass graft surgery and percutaneous coronary intervention.…”

Kidney function and the use of nitrofurantoin to treat urinary tract infections in older women

“…We studied a cohort of older women with relatively low estimated glomerular filtration rate (based on a validated algorithm of diagnosis codes for chronic kidney disease; 19 see Appendix 2) who received a prescription for 1 of 4 oral antibiotics: nitrofurantoin, ciprofloxacin, norfloxacin or trimethoprim-sulfamethoxazole. All of these antibiotics are frequently considered firstline therapy for urinary tract infections.…”

Characteristics and Outcomes of AKI Treated with Dialysis during Pregnancy and the Postpartum Period

“…Whenever possible, we defined pregnancy characteristics andmaternal and perinatal outcomes usingdatabase codesthat have been proven feasible and reliable in prior studies. [26][27][28][33][34][35][36][37] These codes typically have high specificity and modest sensitivity for capturing the variable of interest. Detailed information on coding definitions and validity is provided in Supplemental Table 4.…”