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16-04-2012 | General practice | Article

Benefits of CKD screening ‘uncertain’


Free abstract

MedWire News: There is no direct evidence linking screening for and monitoring of stage 1 to 3 chronic kidney disease (CKD) to improved clinical outcome, show results of a systematic review and meta-analysis.

The study, commissioned by the Agency for Healthcare Research and Quality in the USA, was intended to provide an evidence base to guide recommendations on CKD from the US Preventive Services Task Force and the American College of Physicians Clinical Guidelines Committee.

However, given the insufficient evidence for systematic screening and monitoring of the early stages of CKD, the lack of current guidelines on this subject is "unlikely to change," say editorialists Katrin Uhlig and Andrew Levey from Tufus Medical Center in Boston, Massachusetts, USA.

Lead researcher Howard Fink (Minneapolis Veterans Affairs Medical Center, Minnesota, USA) and colleagues explain that 11% of US adults aged 20 years or older have CKD, of whom 95% have early disease (stages 1 to 3).

CKD is usually asymptomatic until advanced, but can increase the risk for many adverse health outcomes, including cardiovascular disease (CVD), end-stage renal disease (ESRD), and mortality, even in the early stages.

To evaluate the evidence for clinical benefits or harms of screening for and the monitoring and treatment of CKD stages 1 to 3, Fink and team searched the medical literature for randomized controlled trials (RCTs) published between 1985 and 2011.

They found no RCTs evaluating CKD screening in adults who were asymptomatic and no studies monitoring adults with CKD stages 1 to 3 for worsening kidney function or damage.

In spite of this, other studies provide indirect evidence about the benefits and harms of screening. Indeed, clinical and administrative data, primarily from large representative US cohorts, suggest that targeted screening could identify many patients with undiagnosed CKD, while observational studies suggest that targeted CKD monitoring could identify those with unrecognized CKD progression, the researchers report.

Analysis of 110 RCTs evaluating treatment of early-stage CKD showed that angiotensin-converting enzyme (ACE) inhibitors and angiotensin II-receptor blockers reduced ESRD compared with placebo at relative risks (RRs) of 0.65 and 0.77, but the reductions were primarily observed in patients with diabetes who had macroalbuminuria.

In addition, ACE inhibitors reduced mortality versus placebo (RR=0.79) in patients with microalbuminuria and cardiovasculardisease or high-risk diabetes.

The team also found that statins and β-blockers reduced mortality (RRs=0.81 and 0.73, respectively) and cardiovascular events (RR=0.58-0.76 depending on treatment and outcome measure) compared with placebo or controls in patients with impaired estimated glomerular filtration rate and either hyperlipidemia or congestive heart failure.

Writing in the Annals of Internal Medicine, Fink and co-authors conclude: "The role of CKD screening or monitoring in improving clinical outcomes is uncertain."

Nevertheless, Uhlig and Levey say that "targeted screening of clinical populations with a higher risk for CKD and related adverse outcomes, such as patients with CKD risk factors, those with acute illness, and those having diagnostic and therapeutic procedures, rather than untargeted screening may favorably tip the balance of potential benefits versus risks and costs."

By Laura Cowen

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