TABLE 4

Types of Studies in the Literature Based on 350 Articles

Type of StudyPercentage
Descriptive study33.7
Nonrandomized concurrent cohort series32.0
Descriptive study + other10.8
Nonrandomized historical cohort series7.8
Randomized clinical trial4.6
Retrospective3.6
Case-control study1.3
Prospective consecutive cohort series1.3
Cross-sectional population-based survey1.0
Nonrandomized historical cohort series + other1.0
Randomized + other1.0
Undetermined1.0
Nonrandomized concurrent cohort series + other0.7
Experimental study0.3