Table 4. Hospitalization as a predictor of mortality among 842 patients with HIV infection from New South Wales and Western Australia in the Australian HIV Observational Database cohort, 1999–2007.

	Person-years	No. of deaths	Mortality rate per 100 person-years (95% CI)	Univariate hazard ratio (95% CI)	p	Multivariatea adjusted hazard ratio (95% CI)	p	Pb
Total	4547	64	1.4 (1.1–1.8)	–	–	–	–
Hospital admissionsc,d
None	2600	4	0.2 (0.1–0.4)	0.06 (0.02–0.18)	<0.001	0.09 (0.03–0.27)	<0.001
1–3	1474	23	1.6 (1.0–2.4)	1.00		1.00
≥4	473	37	7.8 (5.7–10.8)	6.67 (3.80–11.70)	<0.001	4.37 (2.45–7.78)	<0.001
Age (years)d
<45	2403	26	1.1 (0.7–1.6)	1.00		1.00
≥45	2144	38	1.8 (1.3–2.4)	1.59 (0.96–2.65)	0.073	1.88 (1.11–3.19)	0.019
Sex
Female	267	3	1.1 (0.4–3.5)	1.00		–	–	–
Male	4280	61	1.4 (1.1–1.8)	1.37 (0.42–4.44)	0.603	–	–	–
Hepatitis B virus coinfection
Negative/never tested	4326	61	1.4 (1.1–1.8)	1.00		–	–	–
Positive	221	3	1.4 (0.4–4.2)	0.98 (0.31–3.14)	0.976	–	–	–
Hepatitis C virus coinfection
Negative/never tested	3997	55	1.4 (1.1–1.8)	1.00		–	–	–
Positive	550	9	1.6 (0.9–3.2)	1.19 (0.59–2.41)	0.623	–	–	–
HIV exposure
Homosexual contacte	3706	49	1.3 (1.0–1.8)	1.00		–	–	–
Other	748	14	1.9 (1.1–3.2)	1.37 (0.73–2.58)	0.325	–	–	–
Missing	93	1	1.1 (0.2–7.7)	0.88 (0.12–6.43)	0.900	–	–	–
Time since first positive HIV test (years)d
0–4	413	3	0.7 (0.2–2.3)	1.00		–	–	–
5–7	752	5	0.7 (0.3–1.6)	0.97 (0.23–4.12)	0.964	–	–	–
7–12	1457	27	1.9 (1.3–2.7)	2.76 (0.81–9.42)	0.105	–	–	–
≥12	1886	29	1.5 (1.1–2.2)	2.29 (0.66–7.95)	0.191	–	–	–
Missing	40	0	–	–	–	–	–	–
Prior AIDS
No	3562	43	1.2 (0.9–1.6)	1.00		1.00
Yes	985	21	2.1 (1.4–3.3)	1.77 (1.05–2.98)	0.033	0.87 (0.50–1.51)	0.614
CD4 cell count (cells/μl)d
>200	4125	30	0.7 (0.5–1.0)	1.00		1.00		<0.001
101–200	240	11	4.6 (2.5–8.3)	6.49 (3.24–12.98)	<0.001	3.67 (1.78–7.57)	<0.001
≤100	164	20	12.2 (7.9–18.9)	18.33 (10.31–32.58)	<0.001	6.48 (3.35–12.52)	<0.001
Missing	18	3	17.1 (5.5–52.9)	–	–	–	–
HIV viral load (per 1 log increase, copies/ml)d
≤400	2633	24	0.9 (0.6–1.4)	1.00		1.00		0.012
401–10 000	1052	8	0.8 (0.4–1.5)	1.15 (0.50–2.63)	0.748	1.05 (0.45–2.42)	0.911
≥10 001	842	29	3.5 (2.4–5.0)	4.92 (2.79–8.68)	<0.001	2.01 (1.04–3.87)	0.038
Missing	20	3	14.8 (4.8–45.8)	–	–	–	–
Number of drug classes everd
≤1	555	8	1.4 (0.7–2.9)	1.00		–	–	–
2	1777	22	1.2 (0.8–1.9)	0.84 (0.37–1.89)	0.678	–	–	–
3	2189	34	1.6 (1.1–2.2)	1.03 (0.47–2.26)	0.935	–	–	–
4	26	0	–	–	–	–	–	–
AIDS event after baselined
No	4402	54	1.2 (0.9–1.6)	1.00		1.00
Yes	145	10	6.9 (3.7–12.9)	6.13 (2.98–12.62)	<0.001	1.12 (0.52–2.39)	0.771
Calendar yeard
1999–2000f	465	8	1.7 (0.9–3.4)	1.00		–	–	–
2001	702	10	1.4 (0.8–2.6)	0.56 (0.10–3.17)	0.511	–	–	–
2002	686	6	0.9 (0.4–1.9)	0.22 (0.03–1.89)	0.169	–	–	–
2003	673	7	1.0 (0.5–2.2)	0.60 (0.07–5.33)	0.650	–	–	–
2004	659	13	2.0 (1.2–3.4)	0.43 (0.04–4.40)	0.480	–	–	–
2005	633	8	1.3 (0.6–2.5)	0.41 (0.04–4.35)	0.458	–	–	–
2006–2007g	729	12	1.7 (0.9–2.9)	0.44 (0.04–4.88)	0.503	–	–	–

CI, confidence interval.

^aModel stratified by state.

^bP value for test for homogeneity for nominal, categorical covariates, test for trend for ordinal, categorical covariates.

^cDuring period of follow-up.

^dTime-dependent covariate.

^eInjecting drug use also reported for some participants in this group.

^fIncludes data from 1 July 1999 to 31 December 2000.

^gIncludes data from 1 January 2006 to 31 March 2007.