Except possibly for people with hypertension (high blood pressure), screening for type 2 diabetes provides few benefits, according to a new report from the U.S. Preventive Services Task Force (USPSTF).

Accordingly, revised guidelines from the USPSTF recommend that doctors screen for type 2 diabetes only in adults with sustained high blood pressure above 135 over 80 millimeters mercury (mm Hg).

“Although there is a fair body of evidence that, over a period of years, (blood sugar) control and, especially, cardiovascular risk reduction may improve long-term health outcomes in persons with diagnosed type 2 diabetes, there is very little evidence indicating whether there is an incremental benefit of early treatment as a result of systematic screening of asymptomatic adults,” Dr. Susan L. Norris from Oregon Health & Science University, Portland, Oregon told Reuters Health.

Norris and colleagues reviewed evidence to inform an update of the 2003 USPSTF recommendations on screening for type 2 diabetes and pre-diabetes.

They could identify no randomized controlled trials examining the effectiveness of a screening program for type 2 diabetes and no studies reporting treatment effects in an exclusively screening-detected or recently diagnosed diabetes cohort.

A recent meta-analysis suggested that tight control of blood sugar could result in modest reduction of adverse events in people with type 2 diabetes, the report indicates, but the individual trials in the analysis showed largely nonsignificant results.

There was evidence that persons with diabetes benefit from control of blood pressure and lipid levels, but relevant studies did not include individuals with screening-detected diabetes.

Intensive lifestyle modification in persons with pre-diabetes delays the progression to full-blown diabetes, the researchers note, but whether treatment alters final health outcomes could not be determined from the studies reviewed.

“Aggressive lifestyle changes can dramatically reduce the incidence of diabetes, but it is not clear whether the diagnosis of pre-diabetes confers any particular health benefit over and above what one might expect if all obese patients were counseled to pursue these lifestyle changes,” Norris noted.

Based on the current results, the revised USPSTF guidelines recommend that doctors screen for type 2 diabetes in asymptomatic adults with sustained blood pressure (either treated or untreated) greater than 135 over 80 mm Hg.

“Current evidence is insufficient to assess the balance of benefits and harms of routine screening in asymptomatic adults with blood pressure of 135/80 mm Hg or lower,” the report states.

“We hope that researchers will continue to address the gaps in the current literature,” she concluded.

SOURCE: Annals of Internal Medicine, June 3, 2008.