Table 3 Associations between socioeconomic status constructs and ambulatory care sensitive hospitalization outcomes in included studies (n = 31)

Agabiti, N. et al., 2009 [12]

Rate Ratio

(Lowest income quintile / Highest income quintile)

Chronic (n = 6)

Angina

Asthma

CHF

COPD

Diabetes

Hypertension

2.59

1.97

2.37

3.78

4.23

2.77

1.64

2.35–2.85

1.70–2.30

1.84–3.04

3.09–4.62

3.37–5.31

2.29–3.36

1.31–2.04

(−) As income decreases, hospitalization rate increases.

Begley, C. et al., 2009 [59]

Odds Ratio (Income < 100% of federal poverty level quartile / Income ≥400% of federal poverty level quartile

Epilepsy

Hospitalizations:

4.7 (Unadjusted)

2.9 (Adjusted for age, sex, and clinical characteristics)

0.8 (Additionally adjusted for treatment site)

ER visits:

3.0 (Unadjusted)

2.2 (Adjusted for age, sex, and clinical characteristics)

0.5 (Additionally adjusted for treatment site)

1.4–15.9

0.9–9.9

0.2–3.3

1.6–5.7

1.1–4.3

0.2–1.4

(−) As income decreases, odds of ER visits and odds of hospitalization increases. Adjustment for treatment site mitigates income effect.

Booth, G. et al., 2003 [61]

Odds Ratio

Unadjusted: (Lowest income quintile / Highest income quintile)

Adjusted: Per decline in income quintile

Diabetes

1.43 (Unadjusted)

1.09 (Adjusted for age, sex, rurality, comorbidity, frequency of physician visits, continuity of care, physician speciality, and geographic region)

1.40–1.46

1.08–1.10

(−) As income decreases, odds of hospitalization or ED visits increases.

Chen, P-C. et al., 2015 [62]

Odds Ratio

(Low income quartile / Highest income quartile)

Diabetes

2.89 (Adjusted for age, sex, time of diabetes diagnosis, comorbidities, participation in P4P program, education, and urbanization)

2.44 (Additionally adjusted for health care provider ownership and level)

2.19–3.83

1.81–3.30

(−) As income decreases, odds of hospitalization increases.

Christensen, S. et al., 2011 [63]

Hazard Ratio

(High income tertile / Low income tertile)

CHF

0.67 (Female - Adjusted for age and time period)

0.66 (Male - Adjusted for age and time period)

0.51–0.89

0.42–0.66

(−) As income increases, hospitalization risk decreases.

Davies, S. et al., 2017 [64]

Rate Ratio

(Highest decile of percent population below FPL / Lowest decile of percent population below FPL)

(10th percentile of median income / 90th percentile of median income)

Chronic

Chronic

Asthma

Asthma

1.91 (Percent below poverty line)

1.44 (Median household income)

1.50 (Percent below poverty line)

1.19 (Median household income)

1.78–2.04

1.35–1.53

1.39–1.62

1.11–1.27

(+) As percent below poverty line increases, ED visit risk increases.

(−) As income decreases, ED visit risk increases.

Eisner, M. et al., 2011 [56]

Hazard Ratio

(Low income tertile / High income tertile)

COPD

2.9 (Adjusted for age, sex, race, and education)

2.1 (Additionally adjusted for smoking history, occupational exposures, BMI, and co-morbidities)

1.5 (Additionally adjusted for COPD severity)

1.8–4.5

1.4–3.4

0.9–2.4

(−) As income decreases, hospitalization or ED visit risk increases.

Lofqvist, T. et al., 2014 [14]

Odds Ratio

(Lowest income quintile / Highest income quintile)

Acute and chronic

Ages 18–64:

1.52 (Adjusted for age and sex)

1.12 (Additionally adjusted for marital status, country of birth, education, gainful employment, sickness benefit, and social assistance)

Ages 65–79:

1.28 (Adjusted for age and sex)

1.06 (Additionally adjusted for marital status, country of birth, education, and social assistance)

1.44–1.60

1.06–1.19

1.21–1.36

1.00–1.13

(−) As income decreases, hospitalization rate increases.

Prescott, E. et al., 1999 [74]

Hazard Ratio

(High income tertile / Low income tertile)

COPD

Male:

0.30 (Adjusted for age)

0.32 (Additionally adjusted for smoking status, inhalation, and duration of smoking)

Female:

0.63 (Adjusted for age)

0.59 (Additionally adjusted for smoking status, inhalation, and duration of smoking)

0.20–0.45

0.21–0.49

0.40–1.01

0.37–0.95

(−) As income increases, hospitalization risk decreases.

Quan, H. et al., 2013 [75]

Hazard Ratio

(Highest income quintile / Lowest income quintile)

CHF

0.72

0.71–0.73

(−) As income increases, hospitalization risk decreases.

Shah, R. et al., 2011 [77]

Hazard Ratio

(Lowest income quartile / Highest income quartile)

CHF

3.43 (Unadjusted)

2.60 (Adjusted for age, race/ethnicity, marital status, and treatment assignments)

1.56 (Additionally adjusted for clinical characteristics, health behaviours, and insurance)

2.68–4.38

2.01–3.37

1.19–2.04

(−) As income decreases, hospitalization risk increases.

Walker, R. et al., 2013 [79]

Odds Ratio

(Highest income quintile / Lowest income quintile)

Hypertension

0.59

0.51–0.68

(−) As income increases, odds of hospitalization decreases.

Bocour, A. et al., 2016 [60]

Rate Ratio

(Very high poverty / Low poverty)

Angina

Asthma

CHF

COPD

Diabetes

Hypertension

2.89

5.35

2.61

3.30

3.50

3.03

Missing

(+) As poverty increases, hospitalization rate increases.

Lemstra, M. et al., 2006 [71]

Rate Ratio

(Low income / Affluent)

(Dichotomous)

COPD

Diabetes

1.53

12.86

0.88–2.67

5.42–30.51

(−) As income decreases, hospitalization rate increases.

Li, X. et al., 2008 [72]

Standardized Incidence Ratio

(Low income tertile / All economically active persons

Epilepsy

1.13 (Males)

1.10 (Females)

1.11–1.15

1.07–1.12

(−) As income decreases, hospitalization rate increases.

Roos, L. et al., 2005 [16]

Rate Ratio

(Lowest income quintile / Highest income quintile)

Angina

Asthma

CHF

Epilepsy

1.39

2.90

1.73

2.98

1.21–1.58

2.50–3.37

1.58–1.92

2.17–4.36

(−) As income decreases, hospitalization rate increases.

Bacon, S. et al., 2009 [57]

Risk Ratio

(< 12 years of education / ≥ 12 years of education)

Odds Ratio

(< 12 years of education / ≥ 12 years of education)

Asthma

0.93 (Adjusted for age, sex, and asthma severity)

0.95 (Additionally adjusted for current smoking, BMI, and having a mood and/or anxiety disorder)

1.55 (Adjusted for age, sex, and asthma severity)

1.46 (Additionally adjusted for current smoking, BMI, and having a mood and/or anxiety disorder)

0.90–0.97

0.91–0.99

1.02–2.27

0.98–2.17

(+) As education decreases, risk of ED visits and hospitalizations increases.

(−) As education decreases, odds of ED visits and hospitalizations increases.

Chen, P-C. et al., 2015 [62]

Odds Ratio

(Lowest % of individuals with higher education quartile / Highest % of individuals with higher education quartile)

Diabetes

1.33 (Adjusted for age, sex, time of diabetes diagnosis, comorbidities, participation in P4P program, income, and urbanization)

1.32 (Additionally adjusted for health care provider ownership and level)

1.10–1.61

1.07–1.63

(−) As education decreases, odds of hospitalization increases.

Christensen, S. et al., 2011 [63]

Hazard Ratio

(> 10 years of education tertile / < 8 years of education tertile)

CHF

0.50 (Female - Adjusted for age and time period)

0.53 (Male - Adjusted for age and time period)

0.52 (All - Adjusted for age, sex, and time period)

0.61 (Additionally adjusted for clinical characteristics, BMI, smoking, and physical inactivity)

0.37–0.69

0.42–0.66

0.43–0.63

0.50–0.73

(−) As education increases, hospitalization risk decreases.

Eisner, M. et al., 2011 [66]

Hazard Ratio

(Less than high school education tertile / Post-secondary education completed tertile)

COPD

1.9 (Adjusted for age, sex, race, and education)

1.5 (Additionally adjusted for smoking history, occupational exposures, BMI, and co-morbidities)

1.1 (Additionally adjusted for COPD severity)

1.3–2.7

1.01–2.1

0.7–1.6

(−) As education decreases, risk of hospitalization or ED visit increases.

Prescott, E. et al., 1999 [74]

Hazard Ratio

(> 11 years of education tertile / < 8 years of education tertile)

COPD

Male: 0.44 (Adjusted for age)

0.55 (Additionally adjusted for smoking status, inhalation, and duration of smoking)

Female:

0.27 (Adjusted for age)

0.28 (Additionally adjusted for smoking status, inhalation, and duration of smoking)

0.27–0.72

0.34–0.90

0.11–0.65

0.12–0.69

(−) As education increases, hospitalization risk decreases.

Shah, R. et al., 2011 [77]

Hazard Ratio

(Less than high school tertile / Post-secondary completed tertile)

CHF

2.01 (Unadjusted)

1.96 (Adjusted for age, race/ethnicity, marital status, and treatment assignments)

1.21 (Additionally adjusted for clinical characteristics, health behaviours, and insurance)

1.53–2.65

1.48–2.60

0.90–1.62

(−) As education decreases, hospitalization risk increases.

Li, X. et al., 2008 [72]

Standardized Incidence Ratio

(≤ 9 years of education tertile / All economically active persons)

Asthma

1.03 (Male)

1.05 (Female)

1.01–1.05

1.03–1.08

(−) As education decreases, hospitalization rate increases.

Li, X. et al., 2008 [72]

Standardized Incidence Ratio

(≤ 9 years of education tertile / All economically active persons)

Epilepsy

1.06 (Male)

1.06 (Female)

1.04–1.08

1.04–1.08

(−) As education decreases, hospitalization rate increases.

Li, X. et al., 2008 [72]

Standardized Incidence Ratio

(Unskilled workers / All economically active persons)

Epilepsy

1.04 (Male)

1.01 (Female)

1.02–1.06

0.99–1.03

(−) As occupation decreases, hospitalization rate increases.

Aube-Maurice, J. et al., 2012 [56]

Risk Ratio

(Most deprived quintile / Least deprived quintile)

Hypertension

Males:

1.29 (Material deprivation)

1.14 (Social deprivation)

Females:

1.60 (Material deprivation)

1.04 (Social deprivation)

1.18–1.40

1.05–1.24

1.43–1.79

0.93–1.16

(+) As deprivation increases, hospitalization risk increases.

Govan, L. et al., 2012 [68]

Odds Ratio

(Most deprived quintile / Least deprived quintile)

Diabetes

2.82

2.33–3.42

(+) As deprivation increases, odds of hospitalization increases.

Gupta, R. et al., 2018 [69]

Rate Ratio

(Most deprived quintile / Least deprived quintile)

Asthma

3.34 (Ages 5–44)

2.01 (Ages 45–74)

3.30–3.38

1.98–2.05

(+) As deprivation increases, hospitalization rate increases.

Payne, R. et al., 2013 [15]

Odds Ratio

(Most deprived quintile / Least deprived quintile)

Acute and chronic

2.84 (Unadjusted)

1.98 (Adjusted for age, sex, multimorbidity, and mental health condition)

2.40–3.37

1.63–2.41

(+) As deprivation increases, odds of hospitalization increases.

Shulman, R. et al., 2018 [78]

Rate Ratio

(Most deprived quintile / Least deprived quintile)

Diabetes

(Hospitalizations)

(ER visits)

Values not reported. See Fig. 2 in article.

(+) As deprivation increases, hospitalization and ER visit rate increases.

Asaria, M. et al., 2016 [55]

RII

SII

Chronic

1.06

6.07

1.04–1.07

5.97–6.16

(+) As deprivation increases, hospitalization risk increases.

Banham, D. et al., 2010 [58]

Rate ratio

(Most disadvantaged quintile / Least disadvantaged quintile)

Acute, chronic, and vaccine-preventable

2.5

2.5–2.5

(+) As deprivation increases, hospitalization rate increases.

Disano, J. et al., 2010 [65]

Rate Ratio

(Low SES tertile / High SES tertile)

Aggregate

COPD

Diabetes

2.6

2.7

3

Missing

Missing

Missing

(+) As deprivation increases, hospitalization rate increases.

Fleetcroft, R. et al., 2017 [67]

RII

SII

Diabetes

1.18

84.25

1.15–1.22

81.62–86.88

(+) As deprivation increases, hospitalization risk increases.

Jackson, R. et al., 2001 [70]

Rate Ratio

(Most deprived 10% / Least deprived 40%)

Aggregate

2.3

Missing

(+) As deprivation increases, hospitalization rate increases.

Macleod, M. et al., 2002 [73]

Rate Ratio

(Most deprived septile / Least deprived septile)

Epilepsy

3.30

Missing

(+) As deprivation increases, hospitalization rate increases.

Roberts, S. et al., 2012 [76]

Rate Ratio

(Most deprived quintile / Least deprived quintile)

Asthma

2.48

2.34–2.62

(+) As deprivation increases, hospitalization rate for severe asthma increases.

Sheringham, J. et al., 2017 [13]

SII

Aggregate

5.98

Missing

(+) As deprivation increases, hospitalization risk increases.