Table 2. Summary of literature on mortality and progression to ESRD in CKD stage 4.

Study	Mean age (years)	GFR (ml/min)	Progression to ESRD	Mortality	Population
Keith (2001)	73.6±13.6	15–29	19.9%*	45.7%*	Large HMO
Go (2004)	70.1±14.5	15–29		11.36 per 100 PY‡	Large HMO
Patel (2005)	70.0±10.0	15–29	14.2 per 100 PY	20.1 per 100 PY	Veterans
O'Hare (2007)	65–74	15–29	9.31 per 100 PY	11.68 per 100 PY	Veterans
O'Hare (2007)	75–84	15–29	6.31 per 100 PY	15.39 per 100 PY	Veterans
Roderick (2009)	83.2±7.1	<30		19–29 per 100 PY	UK General Practice
Keough-Ryan (2008)	69.2±13.2	<30	4.27 per 100 PY	33.45 per 100 PY	Post acute cardiac event
Levin (2008)	66.8±14.5	<30	14.3 per 100 PY	4.5 per 100 PY	Referred population
Conway (2009)	Median 71.6	<30	3.8%†	10.4%†	Referred population

*crude data in percentages, over 66 months of follow up.

^†crude 1 year data in percentages.

^‡Age-Standardized Rates.

PY: patient-years.

HMO: Health Maintenance Oraganization.