Prognosis for long-term survival and renal recovery in critically ill patients with severe acute renal failure: a population-based study

Table 1 Risk of sARF associated with selected co-morbidities among adult residents of the Calgary Health Region, Canada

Underlying condition	Number of patients with sARF (n = 240)	Estimated number with underlying condition at risk in CHR	Annual incidence (per 100,000 population)	Relative risk^a (Exact 95% CI)
Heart disease	120	85,576	140	24.0 (18.5–31.2)^b
Stroke	44	21,394	206	22.0 (15.6–31.0)^b
Chronic pulmonary disease	83	68,461	121	16.0 (12.1–21.0)^b
Diabetes mellitus	72	85,576	84	10.3 (7.7–13.6)^b
Cancer	38	42,788	89	9.2 (6.3–13.1)^b
Connective tissue disease	12	21,394	56	5.2 (2.7–9.3)^b
Chronic kidney disease	45	96,273	47	4.9 (3.5–6.8)^b
Alcohol abuse	57	145,480	39	4.3 (3.1–5.8)^b

^aRelative risk calculated by ((Number of sARF patients with underlying condition/Number at-risk with underlying condition in CHR)/(Number of sARF patients without underlying condition/Number at-risk without underlying condition in CHR)). ^bp value < 0.0001 for each underlying condition relative risk. Underlying conditions were defined by using the Charlson Co-morbidity Index [25]. The presence of alcohol abuse was defined by documentation in patient medical record or by history. CHR, Calgary Health Region; CI, confidence interval; sARF, severe acute renal failure.