Development and validation of a self-assessment tool for albuminuria: results from the Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study.

BACKGROUND

The prevalence of albuminuria in the general population is high, but awareness of it is low. Therefore, we sought to develop and validate a self-assessment tool that allows individuals to estimate their probability of having albuminuria.

STUDY DESIGN

Cross-sectional study.

SETTING & PARTICIPANTS: The population-based Reasons for Geographic and Racial Differences in Stroke (REGARDS) Study for model development and the National Health and Nutrition Examination Survey (NHANES) 1999-2004 for model validation. US adults 45 years or older in the REGARDS Study (n = 19,697) and NHANES 1999-2004 (n = 7,168).

PREDICTOR

Candidate items for the self-assessment tool were collected using a combination of interviewer- and self-administered questionnaires.

OUTCOME

Albuminuria was defined as a urinary albumin to urinary creatinine ratio ≥30 mg/g in spot samples.

RESULTS

8 items were included in the self-assessment tool (age, race, sex, current smoking, self-rated health, and self-reported history of diabetes, hypertension, and stroke). These items provided a C statistic of 0.709 (95% CI, 0.699-0.720) and good model fit (Hosmer-Lemeshow χ(2)P = 0.49). In the external validation data set, the C statistic for discriminating individuals with and without albuminuria using the self-assessment tool was 0.714. Using a threshold of ≥10% probability of albuminuria from the self-assessment tool, 36% of US adults 45 years or older in NHANES 1999-2004 would test positive and be recommended for screening. Sensitivity, specificity, and positive and negative predictive values for albuminuria associated with a probability ≥10% were 66%, 68%, 23%, and 93%, respectively.

LIMITATIONS

Repeated urine samples were not available to assess the persistency of albuminuria.

CONCLUSIONS

8 self-report items provide good discrimination for the probability of having albuminuria. This tool may encourage individuals with a high probability to request albuminuria screening.