Thirteen observational studies were included. Seven were cohort studies, five were cross-sectional studies and one was a before-and-after study. Four studies reported their withdrawal or drop-out rates, with completion ranging from 95% to 100%.
Seven cohort studies reported data on survival with conservative management. The median survival ranged from 6.3 to 23.4 months. The following factors were identified by at least one study as predictive of prolonged survival with conservative management: female gender, lower comorbidity score, albumin greater than 35g per litre, and referral to a nephrologist before stage 5 chronic kidney disease.
Five studies included a comparison group of patients on dialysis. Two studies found little or no survival benefit with dialysis, compared with conservative management, whereas three studies found a significant benefit in favour dialysis. There were substantial differences between study groups in all three studies. In one study patients on dialysis had a lower incidence of diabetes than patients on conservative management and more patients on conservative management were socially isolated or late presenters to nephrology. In the second study dialysis patients were significantly younger than patients on conservative management. In the third study conservative management patients were significantly younger and had more comorbidities.
Six studies described the symptom burden and quality of life. All patients undergoing conservative management reported significant symptom burden; the mean number of symptoms ranged from 6.8 to 17. Three studies included a comparative group of dialysis patients, and both groups in all studies were had a similar symptom burden and similar reduced quality of life.