Background: Chronic kidney disease (CKD) is a strong independent predictor of cardiovascular disease. Although general practitioners (GPs) represent the first line for identification of these high-risk patients, their diagnostic approach to CKD is ill defined.
Study design: Cross-sectional evaluation of database of Italian GPs.
Setting & participants: Representative sample of adult Italian population regularly followed up by GPs in 2003.
Outcomes: Frequency of serum creatinine testing, prevalence of CKD (estimated glomerular filtration rate [eGFR] < 60 mL/min/1.73 m(2)), awareness of CKD assessed from use of diagnostic codes (Classification of Diseases, Ninth Revision, Clinical Modification [ICD-9-CM]) for CKD, and referral to nephrologists.
Results: Of 451,548 individuals in the entire practice population, only 77,630 (17.2%) underwent serum creatinine testing. Female sex (odds ratio [OR], 1.09; 95% confidence interval [CI], 1.06 to 1.12), advanced age (OR, 2.70; 95% CI, 2.63 to 2.78), diabetes (OR, 1.31; 95% CI, 1.20 to 1.42), hypertension (OR, 1.10; 95% CI, 1.02 to 1.19), autoimmune diseases (OR, 1.42; 95% CI, 1.11 to 1.82), and recurrent urinary tract infections (OR, 1.63; 95% CI, 1.10 to 2.42) were all associated with serum creatinine testing. Conversely, use of either nonsteroidal anti-inflammatory drugs (OR, 1.03; 95% CI, 0.89 to 1.21) or aminoglycosides or contrast media (OR, 0.78; 95% CI, 0.54 to 1.14) was not associated with serum creatinine testing. In the subgroup with serum creatinine data, the age-adjusted prevalence of CKD was 9.33% (11.93% in women, 6.49% in men). However, in patients with eGFR less than 60 mL/min/1.73 m(2), serum creatinine values were apparently normal (<1.2 mg/dL in women, <1.4 mg/dL in men) in 54%, and GPs used ICD-9-CM codes for CKD in only 15.2%. Referral to nephrologists ranged from 4.9% for patients with eGFR of 59 to 30 mL/min/1.73 m(2) to 55.7% for those with eGFR less than 30 mL/min/1.73 m(2).
Limitations: The prevalence of decreased kidney function may be overestimated because of the more frequent serum creatinine testing in sicker individuals and lack of creatinine calibration.
Conclusions: In primary care, CKD stages 3 to 5 are frequent, but its awareness is scarce because of limited rates of serum creatinine testing and difficulty recognizing decreased eGFR in the absence of increased serum creatinine testing.