Table BSummary of the strength of evidence for KQ 1

Outcome [SOE & Magnitude of Effecta,b,c]Number of Studies (Subjects)SOE Domain–Risk of Bias: Study Design/ QualitySOE Domain–ConsistencySOE Domain–DirectnessSOE Domain–PrecisionEffect Estimate (Range or 95% CI)
Patient Experiences [Moderate SOE: small positive effects]5 (6,884)RCT/FairConsistentDirectPreciseES median (range): 0.27 (−0.36 to 0.42)
2 (3,513)Observational/FairInconsistentDirectPreciseES:d +0.13
Staff Experiences [Low SOE: small to moderate positive effects]2 (NR)RCT/FairInconsistentSome indirectnessImpreciseES median (range): 0.18 (0.14 to 0.87)
1 (82)Observational/FairUnknownDirectImpreciseES median (range): 0.49 (0.32 to 0.61)
Process of Care for Preventive Services [Moderate SOE: small to moderate positive effects]3 (8,377)RCT/FairConsistentDirectPreciseRD median (range): 1.3% (−0.4% to +7.7%)
2 (57,832)Observational/FairConsistentDirectPreciseRD median (range): 14.2% (5.6% to 20.6%)
Process of Care for Chronic Illness Care Services [Insufficient]2 (4,640)RCT/FairInconsistentSome indirectnessPreciseRD median (range): 6.6% (0.2% to 20.8%)
3 (455,832)Observational/FairSeriously inconsistentSome indirectnessPreciseRD median (range): 7.1% (7.1% to 21.4%)
Clinical Outcomes: Biophysical Markers, Health Status, Mortality [Insufficient]3 (2,586)RCT/GoodConsistentSome indirectnessImpreciseNot reliably estimated
3 (58,393)Observational/PoorConsistentSome indirectnessImpreciseNot reliably estimated
Economic Outcomes: Hospital Inpatient Admissions, ED Visits, Total Costse [Low SOE for lower ED visits in older adults and no reduction in admissions; insufficient for total costs in adults; insufficient for all economic outcomes in children]5 (8,001)RCT/FairConsistentSome indirectnessImprecisionAdmissions: RR 0.96 (95% CI, 0.84 to 1.10) in adults;
ED visits: RR 0.81 (95% CI, 0.67 to 0.98) in adults;
total costs: no summary estimate
6 (229,883)Observational/FairConsistentDirectPreciseAdmissions: RD median (range): −0.2% (1.4% to −8.9%);
ED visits: RD median (range): −1.2% (3.1% to −8.3%);
total costs: no summary estimate
Unintended Consequences or Other Harms [Insufficient]0NANANANANo estimate
a

SOE ratings are provided for outcomes overall (incorporating evidence from all studies), while magnitude-of-effect estimates are provided for RCTs vs. observational studies. The effect size for economic outcomes represents a summary estimate of effect from meta-analysis. Other effect sizes are presented as the range across individual studies.

b

In one study, a program of facilitated PCMH (intervention) was compared with providing practices with information on PCMH but not facilitating the implementation (control). This study generally showed no differences on the key outcomes addressed. Both arms implemented components of the PCMH model, and this may be why there were no significant differences between them.

c

The small number of studies conducted among children precluded formal comparison with studies conducted in adults. However, results in these two populations were generally congruent.

d

The effect size for one of the two available observational studies could not be calculated with available information. As a result, an effect size median and range could not be calculated.

e

Two of the 13 studies that reported economic outcomes—1 RCT and 1 observational study—reported only total costs and so did not inform the summary effect estimates reported in this table.

Notes: CI = confidence interval; ED = emergency department; ES = effect size; KQ = Key Question; NA = not applicable; NR = not reported; RCT = randomized controlled trial; RD = risk difference; RR = risk ratio; SMD = standardized mean difference; SOE = strength of evidence

SOE ratings are provided for outcomes overall (incorporating evidence from all studies), while magnitude-of-effect estimates are provided for RCTs vs. observational studies. The effect size for economic outcomes represents a summary estimate of effect from meta-analysis. Other effect sizes are presented as the range across individual studies.

In one study, a program of facilitated PCMH (intervention) was compared with providing practices with information on PCMH but not facilitating the implementation (control). This study generally showed no differences on the key outcomes addressed. Both arms implemented components of the PCMH model, and this may be why there were no significant differences between them.

The small number of studies conducted among children precluded formal comparison with studies conducted in adults. However, results in these two populations were generally congruent.

The effect size for one of the two available observational studies could not be calculated with available information. As a result, an effect size median and range could not be calculated.

Two of the 13 studies that reported economic outcomes—1 RCT and 1 observational study—reported only total costs and so did not inform the summary effect estimates reported in this table.

From: Executive Summary

Cover of Closing the Quality Gap: Revisiting the State of the Science (Vol. 2: The Patient-Centered Medical Home)
Closing the Quality Gap: Revisiting the State of the Science (Vol. 2: The Patient-Centered Medical Home).
Evidence Reports/Technology Assessments, No. 208.2.
Williams JW, Jackson GL, Powers BJ, et al.

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