Table 2. Capacity Increase in Non-ED Settings.

Author (Year)	Design; Country; Duration of Study	Population	Intervention	Effect on ED Use	Effect on Non-ED Use	Other Outcomes
Intervention: Additional Clinic(s)
Chalder et al. (2003)22	Matched time-series analysis England One year before and after	NHS developed walk-in centers with drop-in service Intervention group: 10 towns with walk-in center Control group: 10 similar size towns in same region without walk-in centers	Walk-in centers provided nurse-led, drop-in service with broad hours of operation	Decrease of 173.3 visits/month vs. decrease of three visits/ month in control group (p = 0.11)	Before and after increase of 3.9 visits to primary care facility vs. 23.7 visits in control group (p = 0.25)	None
Hsu et al. (2003)24	Before-and-after observational study with control group England 6 months before and after	NHS developed walk-in centers with drop-in service Intervention group: one town with walk-in center Control group: one nearby town in the same region without walk-in center	Walk-in centers provided nurse-led, drop-in service with broad hours of operation	ED visits increased by 10% (adjusted RR = 1.10; 95% CI = 1.00 to 1.21)	0.10 fewer emergency consultations per day (95% CI = −3.75 to 3.55)	None
O'Kelly et al. (2010)16	Retrospective study Ireland 1999–2007	Single, large ED and out-of-hours general practice emergency service clinic associated with same hospital Intervention group: Dubdoc patients Control group: low-triage-level ED patients	“Dubdoc” is an out-of-hours general practice emergency services clinic	Significant decrease low-triage-level ED visits during Dubdoc hours (54% decrease in low-acuity ED visits vs. 52% decrease outside Dubdoc hours; p < 0.033)	Increase of 102% in “Dubdoc” visits (3,810 in 1999 to 7,696 in 2007)	Not reported
Rust et al. (2009)19	Cohort study United States 2003–2005	Rural counties in state of Georgia Intervention group: counties with CHCs (n = 24) Control group: counties without federally funded CHCs (n = 93)	CHCs provide care to the uninsured without medical homes	Non-CHC counties had higher rates of ED visits (RR = 1.21; 95% CI = 1.02 to 1.41)	None reported	None reported
Intervention: Change in scheduling/hours
Hudec et al. (2010)15	Case-comparison study before-and-after advance access implementation Canada 3 months	Four family physician practices Intervention group: patients of general practice with advanced access booking Control group: patients of three general practices with traditional booking	Practice instituted a model in which most appointments are same-day access	28% reduction in low-acuity ED visits in group	None	7% revenue increase for practice Improved self-reported patient satisfaction (p < 0.05)
Philips et al. (2010)23	Before-and-after observational study with control group Belgium 2006–2007	Formation of GPCs Intervention group: city (Turnhout) that implemented GPC Control group: two other large cities that did not have GPC (Ghent and Antwerp)	GPC reorganized providers for that region and centralized out-of-hours primary health center, open on weekends and holidays	815 visits to ED before and 791 visits post (no significant change)	Primary care visits increased in the intervention region (714 to 1197 visits) (OR = 1.37; 95% CI = 1.20 to 1.57), while stayed relatively constant in control region (734 to 850 visits)
Solberg et al. (2004)20	Retrospective pre–post study United States 1999–2001 Risk adjusted	Large, multispecialty medical group Patients with three select chronic conditions (heart disease, diabetes, depression) Intervention group: 17,376 patients in 2001 after implementation of open access Control group: 16,099 patients in 1999 before implementation of open access	Full advanced access appointments introduced, which included standardization of schedule slots and extra visit time for clinicians	No significant difference in risk-adjusted proportion of patients visiting ED (during this time period, ED visits also increased by 7.8% for the medical group) (all p > 0.05)	Increase in primary care visits (all p < 0.01) Significant decrease in risk-adjusted proportion of patients visiting urgent care (all p < 0.001)	Total cost per patients increased 10%–20% depending on condition Significant reduction of proportion of patients with hospitalizations (1%) and length of stay >3 days (4%) for heart disease patients only (nonsignificant changes for other conditions)
Solberg et al. (2006)21	Retrospective pre–post study United States 1999–2001 Risk adjusted	Large, multispecialty medical group owned by health plan Intervention group: 6,609 patients with depression in 2001 after implementation of open access Control group: 7,284 patients with depression in 1999 before implementation of open access	Advanced access appointments instituted (third next-day available appointment reduced from 19.4 to 4.5 days)	No significant change in ED visits	1% increase in primary care visits (p < 0.01) 2% increase in hospitalizations (p < 0.05)	17.6% reduction in proportion of patients with no follow-up after starting new medication (p = 0.001) Majority of visits with one physician (continuity of care) increased by 6.7% (p < 0.001)
van Uden et al. (2004)17	Retrospective pre–post cohort study Limburg, the Netherlands	Regional general practitioner cooperatives Intervention group: 12,319 patient contacts after implementation of GPCs Control group: 11,781 patient contacts before implementation of GPCs	Large cooperatives of general practitioners to offer out of hours primary care, also act as gatekeeper for ED visits	9% decrease in ED visits after hours 13.7% absolute reduction number of self-referrals to ED	10% increase in primary care visits after hours 4.6% increase in overall patient contacts after hours 3.6% shift in use from ED to primary care (p < 0.001)	None
Wang et al. (2005)18	Pre–post intervention study with comparison group United States 12 months	Large, private, primary care pediatric practice with Medicaid patients Intervention group: 17,382 children in the enhanced access program Control group: 26,066 Medicaid-eligible children who received services from other local community primary care providers	Increased care coordination, case management, expanded after-hours clinics and walk in hours at clinic	20% reduction in ED utilization for the intervention group (p = 0.007)		Cost per member per month was $8.53 was found in the control group and $7.17 in intervention group, thus a comparative savings of 16%

CHCs = community health centers; GPCs = group practitioner cooperatives; RR = rate ratio.