Study Characteristics
The baseline descriptive characteristics (country, sample size and age) of the 9 studies included in the systematic review were summarized in Table 1. Four studies (19 -22 )were from the United States, Korea had two studies(23 , 24 ), the others originated from German(25 ), Australia(26 ), Sweden(27 ). The mean age of KTx ranged from 42.4 to 53.6 years, and all studies included both men and women. The duration of the interventions ranged from 3 to 12 months. The longest follow-up was one year.
Table 1. Descriptive summary of included studies.