National Analgesic Nephropathy Study (NANS)

NANS_LogoObjectives

To determine whether non-contrasted computerized tomography (CT) among patients with end stage renal disease (ESRD) can be used with adequate precision to identify cases of analgesic nephropathy (AN) as a unique entity. If AN can be identified, to determine which analgesics, including combination analgesics, are associated with its development, and to determine the effects of duration of exposure and dosage. If AN can be identified, to determine its incidence and the proportion of the total burden of ESRD in the U.S that it represents. Whether or not the CT identifies AN, to determine the relation of analgesic use (the effects of specific drugs, duration of exposure, and dosage) to the de novo onset of chronic renal insufficiency in general.

Methods

Male and female patients with ESRD who have begun hemodialysis not more than 30 days previously were enrolled from dialysis clinics in North Carolina and Ohio, and Texas. One normal control, identified from drivers’ license or social security records, was enrolled and interviewed for most ESRD patients, matched for race, decade of age, sex, and region. Data was obtained at the local study centers by CT scan (cases only) and interview (cases and controls). The interview information will include a comprehensive renal history, and information on lifetime use of analgesics taken for at least three months. The study was conducted in two phases.

Phase I was devoted to methodological development, including the questionnaire that was used in Phase II, the CT scan parameters to be used as criteria for AN, and other aspects of the methods. Various aspects of the study procedures and instruments were tested in ESRD patients and normal subjects. The main objective of Phase II is the assessment of the performance of the questionnaire and CT scan criteria in a group of patients from an area of the country where the putative incidence and prevalence of AN is high (North Carolina), and a group from areas of the country where the incidence is thought to be modest to low (Ohio and Texas). Totals of 241 cases and 207 controls were included in the final analyses.

Results

The results demonstrated that the CT scan is not a sensitive method for identifying heavy analgesic users among ESRD patients in the U.S. The data have also provided a valuable resource for the exploration of many additional topics concerning radiological and other aspects of ERSD.