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Table 1 Summary of included studies categorised on study outcomes

From: Effects of continuity of care on health outcomes among patients with diabetes mellitus and/or hypertension: a systematic review

Authors (year)

Country

Design

N

Agea

Length (years)

CoC measurement

CoC cut-off

Results

w/ Improvement

w/o improvement

I. Health indicators

 Hanninen, Takala et al. (2001) [31]

Finland

Cross-sectional

DM: 260

 < 65

2

Single ph.

Same ph. ≥ 2 years

 

HbA1c

BMI

 Overland, Yue et al. (2001) [32]

Australia

Prospective cohort

DM: 479

Single GP: 59.9 (50.7–67.0)

Multiple GP: 54.0 (48.7–61.5)

0.5

Single ph.

Single ph.

 

HbA1c

Blood pressure

Lipid profile

 Parchman and Pugh (2002) [33]

United States

Prospective cohort

DM: 265

58.7 (9.7)

2

CoCI

No cut-off

HbA1c

 

 Sherina, Teng et al. (2003) [49]

Malaysia

Cross-sectional

DM: 166

59.2

 < 1

UPCI

Median

 

HbA1c

 Mainous, Koopman et al. (2004) [34]

United States

Prospective cohort

DM: 1400

No summary

6

Usual ph./site by patient questionnaire

w/ usual ph./site

HbA1c

Blood pressure

LDL

 Litaker, Ritter et al. (2005) [50]

United States

Retrospective cohort

DM: 1448

No summary

1

Single ph.

Same ph. for 1 year

 

HbA1c

Blood pressure

 Fisher, Sloane et al. (2007) [25]

United States

Retrospective cohort

HT: 459

58.9 (14.8)

2

CoCI

0.40 (low/med)

0.67 (med/high)

 

Blood pressure

 Gulliford, Naithani et al. (2007) [35]

United Kingdom

Prospective cohort

DM: 193

65

 < 1

Experienced CoC by patient questionnaire

No cut-off

 

HbA1c

Blood pressure

BMI

 Salzman, Yuen et al. (2006) [30]

United States

Retrospective cohort

HT: 287

 ≥ 18

3

Single ph.

Same ph. of last 5 visits

 

Blood pressure

 Dearinger, Wilson et al. (2008) [36]

United States

Retrospective cohort

DM: 101

61.8

3

UPCI

0.45 (low/high)

HbA1c

Blood pressure

LDL

 Younge, Jani et al. (2012) [51]

United States

Retrospective cohort

DM: 484

 ≥ 18

2

MMCI

Quartiles

HbA1c

LDL

Blood pressure

 Hanafi, Abdullah et al. (2015) [27]

Malaysia

Retrospective cohort

HT: 1060

62.0 (10.4)

1

UPCI

No cut-off

 

Blood pressure

 Liao, Lin et al. (2015) [52]

Taiwan

Retrospective cohort

DM: 89,428

53.7 (11.1)

10

UPCI (ph. & site)

1.0 in ph. (high)

1.0 in site (high)

 < 0.7 in both ph. & site (low)

Others (med)

Complications (CVD, PVD, renal diseases and others)

Hospitalisation

Mortality rate

 

 Lustman, Comaneshter et al. (2016) [42]

Israel

Retrospective cohort

DM: 23,294

High UPCI: 61.1

Low UPCI: 59.7

2

UPCI

0.75 (low/high)

Mortality rate

HbA1c

Blood pressure

Hospitalisation

LDL

 Chang, Chien et al. (2018) [53]

Taiwan

Retrospective cohort

DM: 26,063

55.8 (12.0)

17

CoCI

0.43 (low/med)

0.80 (med/high)

Complication (ESRD)

Hospitalisation

 

 Jang, Choy et al. (2018) [54]

South Korea

Retrospective cohort

DM: 3565

No summary

8

CoCI

0.75 (low/high)

Complication (ESRD)

 

 Khanam, Kitsos et al. (2019) [28]

Australia

Retrospective cohort

HT: 37,425

 ≥ 18

3.5

HHI

0.5 (low/med)

0.75 (med/high)

1 (max)

Blood pressure

 

 Kim and Park (2019) [48]

South Korea

Case–control

DM: 55,558

No death: 76.7 (7.0)

w/ death: 76.7 (7.1)

12

UPCI (site)

Lowest vs highest by SAS Rank

Mortality rate

 

 Lee, Chun et al. (2019) [47]

South Korea

Retrospective cohort

DM: 16,806

 > 45

12

CoCI

0.75 (low/high)

Complication (thyroid disorder)

 

 Leniz and Gulliford (2019) [62]

Chile

Cross-sectional

HT: 1252

DM: 418

 ≥ 15

2

Questionnaire

No cut-off

 

HbA1c

Blood pressure

 Nam, Lee et al. (2019) [55]

South Korea

Case–control

DM: 2373

 ≥ 20

10

CoCI

Median

Complications (CVD, nephropathy and others)

Healthcare expense

 

 Sousa Santos, Tavares Bello et al. (2019) [46]

Portugal

Retrospective cohort

DM: 100

Studied: 69.2 (10.6)

Control: 67.2 (10.4)

5

Single ph.

Same ph. ≥ 5 years

HbA1c

Blood pressure

BMI

LDL

 Choi, Choi et al. (2020) [29]

South Korea

Retrospective cohort

HT: 244,187

 ≥ 20

11

CoCI

0.23, 0.36, 0.56

Complication (CVD)

 

II. Service Utilisation

 Knight, Dowden et al. (2009) [56]

Canada

Retrospective cohort

DM: 1143

 ≥ 65

3

CoCI

UPCI

SECON

0.75

Hospitalisation

 

 Hong, Kang et al. (2010) [10]

South Korea

Retrospective cohort

HT: 858,927

DM: 268,220

HT: 71.5 (5.0)

DM: 70.6 (4.6)

4

CoCI

0.20 (low/med)

0.40 (med/high)

Hospitalisation

A&E attendance

 

 Lin, Huang et al. (2010) [37]

Taiwan

Retrospective cohort

DM: 6476

58.8 (12.7)

5

UPCI

0.47 (low/med)

0.75 (med/high)

Long-term hospitalisation

Short-term hospitalisation

 Liu, Doug et al. (2010) [57]

United States

Retrospective cohort

DM: 3873

58.7 (58.3–59.1)

2

FCI (site)

No cut-off

A&E attendance

 

 Chen and Cheng (2011) [13]

Taiwan

Retrospective cohort

DM: 48,107

60.7 (11.3)

7

CoCI

0.47 (low/med)

0.86 (mid/high)

Hospitalisation

A&E attendance

Medication expense

Healthcare expense

 

 Robles and Anderson (2011) [7]

United States

Retrospective cohort

HT: 5590

Low CoCI: 76.2

Intermediate: 75.7

High CoCI: 75.9

1

CoCI

0.106 (low/med)

0.236 (med/high)

 

Medication expense

 Worrall and Knight (2011) [38]

Canada

Retrospective cohort

DM: 305

74.3(6.7)

3

UPCI

0.75 (low/high)

Mortality rate

Hospitalisation

 

 Chen, Tseng et al. (2013) [18]

Taiwan

Retrospective cohort

DM: 11,299

55.7(11.3)

7

CoCI

0.22 (low/med)

0.44 (med/high)

Hospitalisation

A&E attendance

 

 Hong and Kang (2013) [39]

South Korea

Retrospective cohort

DM: 68,469

53.6 (12.1)

4

CoCI

0.4, 0.6, 0.8, 1

Mortality rate

Hospitalisation

Healthcare expense

 

 Hussey, Schneider et al. (2014) [40]

United States

Retrospective cohort

DM: 166,654

 > 65

2

CoCI (ph./site)

No cut-off

Hospitalisation

A&E attendance

Complications (MI, renal diseases and others)

Healthcare expense

 

 Comino, Islam et al. (2015) [58]

Australia

Retrospective cohort

DM: 20,433

 ≥ 45

1.5

UPCI

0.80

Hospitalisation

 

 Cho, Nam et al. (2016) [59]

South Korea

Retrospective cohort

DM: 5163

 ≥ 20

9

CoCI

0.2, 0.4, 0.6, 0.8, 1

Hospitalisation

 

 Hsu, Chou et al. (2016) [41]

Taiwan

Retrospective cohort

DM: 3757

No summary

7

CoCI

Low, medium, high (= 1)

A&E attendance

 

 Nam, Cho et al. (2016) [26]

South Korea

Retrospective cohort

HT: 3,460,700

 ≥ 20

3

CoCI

0.75 (low/high)

Hospitalisation

 

 Pu and Chou (2016) [61]

Taiwan

Retrospective cohort

HT: 331,506

DM: 82,181

HT:

w/ A&E: 71

No A&E: 66

DM:

w/ A&E: 69

No A&E: 65

2

CoCI

HT:

0.46 (low/med)

0.82(med/high)

DM:

0.43 (low/med)

0.72(med/high)

A&E attendance

 

 Van Loenen, Faber et al. (2016) [43]

the Netherlands

Cross-sectional

DM: 45,082

No summary

3

ph. and patient questionnaires

No cut-off

 

Hospitalisation

 Weir, McAlister et al. (2016) [44]

Canada

Prospective cohort

DM: 285,231

53.0 (10.5)

7

UPCI

0.75 (low/high)

Mortality rate

Hospitalisation

 

 Li (2019) [45]

Taiwan

Retrospective cohort

DM: 4007

High CoCI: 61.1 (10.6)

Low CoCI: 60.8 (10.5)

High UPCI: 61.1 (10.6)

Low UPCI: 60.8 (10.5)

3

CoCI

UPCI

Median (low/high)

Hospitalisation

A&E attendance

Mortality rate

 Chen and Cheng (2020) [60]

Taiwan

Retrospective cohort

DM: 57,965

56.3

4

CoCI

Tertiles

Hospitalisation

 
  1. HT Hypertension, DM Diabetes mellitus, ph. Physician, CoC Continuity of care, CoCI Continuity of care index, UPCI Usual provider continuity index, SECON Sequential continuity index, MMCI Modified modified continuity index, FCI Fragmentation of care index, HHI Herfindahl–Hirschman index, A&E Accident and emergency, HbA1c Haemoglobin A1c; “Blood pressure” refers to either systolic blood pressure, diastolic blood pressure and a combined target of the two, BMI Body mass Index; “Lipid profile” (unless specified) refers to either levels of low density lipoprotein, high density lipoprotein, cholesterol or triglyceride, LDL Low-density lipoprotein; “Complications” refers to (but not limited to) onset of cardiovascular disease, end-stage renal disease etc., ESRD End-stage renal disease, CVD Cardiovascular diseases, MI Myocardial infarction, w/ With, w/o Without, N Number
  2. aAge summary was extracted based on the availability of the information by the following order: mean (SD), median (interquartile range), median, mean or range