CLN Article

Diagnostic Profiles

In This Issue...

Guideline-Recommended HCV RNA Testing Lacking in One-Third of Patients

New York City Department of Health and Mental Hygiene (DOHMH) researchers determined that one-third of hepatitis C virus (HCV) antibody-positive patients did not receive guideline-recommended RNA testing to determine their HCV infection status (Am J Med 2013;126:718–22). The findings highlight the need to educate clinicians and counselors about the importance of HCV RNA testing so that it is performed for more patients, according to the authors. They also called for routine HCV RNA reflex testing for all positive HCV antibody tests, in the same way that Western blot testing became a routine step in HIV testing.

For 2 months, the authors randomly sampled cases that had been reported to the DOHMH with positive HCV results as part of the agency's HCV surveillance requirements. Of 260 such cases, they ultimately investigated 245. At the time of DOHMH's initial assessment, 90 patients lacked HCV RNA testing. Even after DOHMH requested testing for these patients, 81 (33%) still did not have HCV RNA testing. The investigators followed up with clinicians to discover why the testing had not been ordered. The most frequent reason given was patients not returning for the test (34.6%), followed by patients being seen in facilities that did not perform HCV RNA testing or that referred patients elsewhere for testing (22%). Patients who did not have RNA testing were seen in medical facilities (47%), detox facilities (30%), and incarceration facilities (15%).

The researchers called not only for educating clinicians about the importance of HCV RNA testing but also allocating appropriate resources to make this testing available and affordable in facilities that screen for HCV.

Long-Term Glycemic Control Linked to Reduced ESRD in Type 1 Diabetics

In a tip-of-the-hat to the increasing emphasis placed on blood pressure and glycemic control among diabetics, a decades-long study found a lower prevalence and incidence of end-stage renal disease (ESRD) among type 1 diabetics more recently diagnosed in comparison to those who had been living longer with the disease (Diabetes Care 2013 doi: 10.2337/dc13-1287). The findings point to the importance of intensive diabetes management even in long-standing diabetics to forestall development of ESRD.

The Wisconsin Epidemiologic Study of Diabetic Retinopathy (WESDR) involved more than 10,000 patients with diabetes being followed in the community in 1979–1980 and classified as older or younger in diabetes onset. The current study involved nearly 1,000 WESDR subjects examined at the study's baseline in 1980 and at 4–25 years' follow-up. The authors previously reported an inverse relationship between prevalence of proliferative retinopathy and shorter duration of years since diabetes diagnosis, and they wanted to see if a similar pattern existed for ESRD.

At the study's baseline, mean HbA1c was 10.1% and just 16% of patients were taking antihypertensive medications, with 3% reporting a history of renal transplant or dialysis, the authors' criteria for ESRD. However, at the study's 25th year, mean HbA1c was 7.5% and more than 54% of participants took antihypertensive agents. By then, 13% of subjects reported a history of ESRD.

In looking closer at these associations, the authors found that in patients diagnosed with diabetes between 1970–1980, the unadjusted cumulative incidence of ESRD at 25 years was 9.3%. The unadjusted hazard of ESRD was 70% lower compared with those diagnosed between 1922–1969. HbA1c levels, systolic blood pressure, and antihypertensive therapy attenuated this association, but HbA1c, age, and male sex remained associated with risk of ESRD after adjustments for kidney function and proliferative retinopathy.