Variation in clinical outcomes and process of care measures in community acquired pneumonia: a systematic review.

There is consistent evidence of moderate quality for significant variation in length of stay and process of care measures but not for in-patient mortality or hospital re-admission. Evidence linking variation in outcomes with variation in process of care measures was limited; where present no difference in mortality was detected despite POC variation. Adjustment for natural variation within studies was lacking; the proportion of observed variation due to chance is not quantified by existing evidence.