Table 2.
Sensitivity analysis of the effect of recent homelessness or unstable housing on risk of HIV or HCV acquisition in PWID compared with PWID who are not homeless or are stably housed
| Number of estimates | Effect size (95% CI) | p value | I2 | pheterogeneity | |
|---|---|---|---|---|---|
| Effect on risk of HIV acquisition | |||||
| Unadjusted effect estimates | 17 | 1·55 (1·23–1·95) | 0·0002 | 62·7 | 0·0003 |
| Adjusted effect estimates | 9 | 1·39 (1·06–1·84) | 0·019 | 65·5 | 0·0031 |
| Published unadjusted estimates | 5 | 1·65 (1·11–2·44) | 0·012 | 77·3 | 0·0015 |
| Unpublished unadjusted estimates* | 12 | 1·46 (1·12–1·91) | 0·0048 | 42·7 | 0·058 |
| Only longitudinal studies | 15 | 1·62 (1·27–2·07) | 0·0001 | 63·4 | 0·0005 |
| Only studies with hazard ratios | 10 | 1·56 (1·08–2·25) | 0·018 | 73·5 | <0·0001 |
| Only studies with at least 90% of participants injecting recently | 11 | 1·44 (0·97–2·13) | 0·068 | 75·4 | 0·0001 |
| Only studies at low-to-moderate risk of bias | 10 | 1·56 (1·14–2·12) | 0·0052 | 72·6 | 0·0001 |
| Estimate for homelessness | 12 | 1·44 (1·13–1·83) | 0·0036 | 52·7 | 0·016 |
| Estimate for unstable housing | 5 | 1·82 (1·13–2·95) | 0·014 | 67·8 | 0·014 |
| Effect on risk of HCV acquisition† | |||||
| Unadjusted effect estimates | 28 | 1·65 (1·44–1·89) | <0·0001 | 44·8 | 0·0060 |
| Adjusted effect estimates | 14 | 1·64 (1·43–1·89) | <0·0001 | 9·6 | 0·35 |
| Published unadjusted estimates | 11 | 1·61 (1·18–2·19) | 0·0029 | 66·9 | 0·0008 |
| Unpublished unadjusted estimates* | 17 | 1·69 (1·49–1·92) | <0·0001 | 14·2 | 0·29 |
| Only longitudinal studies | 25 | 1·61 (1·40–1·86) | <0·0001 | 38·6 | 0·027 |
| Only studies with hazard ratios | 18 | 1·59 (1·36–1·86) | <0·0001 | 45·6 | 0·019 |
| Only studies with at least 90% of participants injecting recently | 20 | 1·54 (1·32–1·80) | <0·0001 | 39·0 | 0·039 |
| Only studies at low-to-moderate risk of bias | 19 | 1·67 (1·37–2·03) | <0·0001 | 52·4 | 0·0042 |
| Estimate for homelessness | 19 | 1·66 (1·37–2·00) | <0·0001 | 55·3 | 0·0018 |
| Estimate for unstable housing | 10 | 1·72 (1·48–1·99) | <0·0001 | 0·0 | 0·47 |
HCV=hepatitis C virus. PWID=people who inject drugs.
Unpublished estimates are those that have been calculated from raw data for the current study and have not been presented in previously published papers.
One study (unpublished estimate, provided by Wijnand and colleagues) provided estimates for both unstable housing and homelessness. For all sensitivity analyses, the effect of unstable housing from this study was used, except when pooling estimates specifically for homelessness or unstable housing. Hence, the number of studies for these two sensitivity analyses add up to 29.