Table 2

GRADE assessment of certainty of estimate of effect size and summary of findings

OutcomeGRADE assessment of certainty*Summary of findingsAbsolute effect estimates
Risk of biasInconsistencyIndirectnessImprecisionPublication biasCertaintyNumber of studiesHF/TAU participantsEffect estimate (95% CI)Outcomes in control†Outcomes in HFEffect (95% CI)
Mental healthSelf-rated mental healthSerious (−1)None‡NoneNoneUnlikely+++, moderate21359/1194SMD=0.07 (−0.19 to 0.33)14.4—gain in score (out of 100) across 24 months15.53—gain in score+1.13 difference in mean change (−3.06 to +5.31)
Quality of lifeSelf-rated physical healthSerious (−1)NoneNoneNoneUnlikely+++, moderate21359/1194SMD=0.00 (–-0.09 to 0.09)6.5—gain in score (out of 100) across 24 months6.5—gain in score (out of 100) across 24 monthsno difference in mean change (−1.14 to +1.14)
Substance useProblematic substance useSerious (−1)NoneNoneNoneUnlikely+++, moderate2465/456 Several outcomes analysed showing no meaningful difference in changes in problematic substance use between groups across 24 months
Health service useHospitalisationsSerious (−1)NoneNoneNoneUnlikely+++, moderate2516/519IRR=0.76 (0.70 to 0.83)1480 hospitalisations per 1000 person-years1125 hospitalisations per 1000 person-years355 fewer hospitalisations (252 to 444)
Time spent hospitalisedSerious (−1)Serious (−1)NoneNoneUnlikely++, low3898/839SMD=−0.14 (−0.41 to 0.14)6379 days spent hospitalised per 1000 person-years6372 days spent hospitalised per 1000 person-years7 fewer days (7 more days to 20 fewer)
Emergency department visitsSerious (−1)None§NoneSerious (−1)¶Unlikely++, low**21359/1194IRR=0.63 (0.48 to 0.82)2056 emergency department visits per 1000 person-years1295 emergency department visits per 1000 person-years761 fewer emergency department visits (370 to 1069)
Housing stabilityAttaining stable housingSerious (−1)NoneNoneSerious (−1)¶Unlikely++, low3985/1000RR=2.46 (1.58 to 3.84)37 persons per 100 stably housed at 24 months75 persons per 100 stably housed at 24 months†† 38 more persons stably housed (31 to 46)††
Time spent stably housedSerious (−1)NoneNoneSerious (−1)¶Unlikely++, low21257/1116SMD=1.24 (0.86 to 1.62)235 days per person spent stably housed in 24 months497 days per person spent stably housed in 24 months261 more days stably housed (181 to 432)
  • *For all health outcomes, certainty was assessed as either certainty of direction of effect or certainty of null effect. For housing stability outcomes, assessment was made around effect size,42

  • †Control means calculated from all useable control data.

  • ‡High heterogeneity was deemed to be explained by differences in effect by age group, therefore not downgraded.

  • §All effects in same direction with high confidence of non-null effect; rated ‘none’ despite high I2.

  • ¶Score reduction of ‘−1’ here on the basis of relatively small concerns across both inconsistency and imprecision.

  • **Rated ‘low’ for certainty of effect direction; ‘very low’ for certainty of effect size.

  • ††Absolute effect size recalculated from proportion of each group stably housed.

  • HF, Housing First; IRR, incidence rate ratio; RR, risk ratio; SMD, standardised mean difference; TAU, treatment as usual.