The relationship between methodological trial quality and the effects of impregnated central venous catheters

We assessed the methodological trial quality of individual randomized controlled studies on chlorhexidine silver sulfadiazine impregnated catheters and the effect on catheter-related infection (CRI).

Only the studies identified in the Medline database from 1966 to December 2001 were considered, abstracts being excluded. The outcome of this investigation centered on bloodstream CRI. The trial quality of the 11 studies identified and published (total 3,131 catheters) was assessed using a scoring system based on allocation, patient selection, patient characteristics, blinding of the intervention and the diagnosis of CRI (range 0-2 points, 10 points maximum).

The mean methodological quality score was 7.1 (range 5-9). The relative risk reduction for bloodstream CRI ranged from -0.14 to 1.0. No association between trial quality and the impact of chlorhexidine silver sulfadiazine impregnated catheters on CRI was found. The summary odds ratio for CRI was 0.69 (95% CI 0.46-1.03). Taking only those studies with 2 points for diagnosis of CRI a summary odds ratio of 0.87 (95% CI 0.44-1.72) resulted, whereas studies with a diagnosis score of only 1 point led to a summary odds ratio of 0.60 (95% CI 0.35-1.02).

The quality of the studies seems to have had no influence on the outcome, according to the results of this investigation, but the use of only a single quality score may not be sufficient to investigate the prevention effect of impregnated catheters.