Data extraction of studies included in systematic review
| Study & year published | Country | Design | Method and Description | Number of articipants & Ethnic Group | Age description | Duration of Study | Key Outcomes | ||||
| Papers assessing T1DM comorbidities | |||||||||||
| Brabarupan et al 12 (2013) | UK | Cross-sectional study |
Ethnicity Grouped into WE, African and SA T1DM Diagnosis of T1DM and diagnosed <35 years of age Method Data from patients from WE, African or SA ancestry were obtained from an electronic database in a large multiethnic London diabetes clinic | 642 individuals in total WE: 564 SA: 39 African: 39 | Median age at diagnosis (years) WE: 16.7 African: 19.4 SA: 19.1 | N/A | Parameters median (IQR) BMI (kg/m2) Systolic BP (mm Hg) Diastolic BP (mm Hg) HbA1c (%) Microalbuminuria (mg/mmol) Total cholesterol (mmol/L) HDL (mmol/L) Triglyceride (mmol/L) | WE 25.0 (22.3–27.7) 130 (119–141) 75 (69–81) 8.0 (7.1–8.9) 1.2 (−0.5–3.0) 4.50 (3.90–5.10) 1.49 (1.21–1.77) 0.93 (0.59–1.28) | African 25.7 (22.5–28.9) 135 (121–149) 80 (72–88) 9.1 (7.6–10.7) 3.7 (−44.5–51.9) 4.40 (3.90–4.90) 1.25 (0.95–1.56) 0.99 (0.58) | SA 25.3 (22.2–28.5) 122 (1120133) 73 (67–79) 8.3 (7.5–9.2) 1.2 (−1.4–3.8) 4.00 (3.2–4.8) 1.30 (1.47–1.14) 1.07 (0.76–1.39) | Significant p<0.05 p<0.05 p<0.05 p<0.05 p<0.05 p<0.05 |
| Sarwar et al 9 (2015) | UK | Cross-sectional study |
Ethnicity SA and WE T1DM Coding of T1DM from the clinical database of two centres—no diagnostic criteria included Method Data analysed from two centres in the West Midlands (QEH and NCH) | WE: 278 SA: 139 | Median age (years) NCH WE: 34 NCH SA: 33.5 QEH WE: 36 QEH SA: 36 | N/A |
Characteristic (no of patients) HbA1c (mmol/mol) Systolic BP (mm Hg) Diastolic BP (mm Hg) BMI (kg/m2) Total cholesterol (mmol/L) HDL (mmol/L) Cholesterol/HDL Creatinine level (µmol/L) eGFR (mL/min/1.73 m2) Albumin/creatinine ratio (mg/mmol) |
NCH South Asian (80) 75 (61.5–88.5) 121 (113–132) – 25.6 (22.55–28.4) 4.7 (3.9–5.45) 1.3 (1.0–1.6)* 3.6 (2.9–4.5)* 75 (66–87) 97.3 (82.2–109.9) 2.4 (0.7–3.6) |
NCH Caucasian (160) 76 (63–91) 125 (115–132) – 25.7 (22.5–30.4) 4.6 (4–5.3) 1.4 (1.2–1.65)* 3.2 (2.7–4.0)* 78 (69–87) 91.2 (79.3–103.9) 2.5 (0.75–3.5) |
QEH South Asian (59) 66.1 (55.25–81.75) 130 (120.5–141.5) 86 (80.5–90)* 30.9 (22.8–37) 4.45 (3.8–5.45) – – – – – |
QEH Caucasian (118) 70.5 (61–83.6) 131.5 (120.3–144) 82 (77.25–88.75)* 25 (22.6–28) 4.1 (3.7–4.95) – - - – – |
| Shenoy et al 10 (2004) | UK | Retrospective observational study |
Ethnicity SA and WE T1DM Children coded as T1DM in a centre in Leicestershire—no diagnostic criteria included Method Rates of obesity/overweight in WE and SA groups and to correlate these with age, duration of diagnosis, daily insulin requirement and HbA1c Included children between the ages of 2 and 18 years and who had been diagnosed more than a year ago | WE: 112 SA: 38 |
Age group (n) 2–4 years (3) 5–9 years (33) 10–15 years (90) 16–18 years (24) | N/A |
Demographic data No statistically significant difference in the two subgroups in relation to age, duration of diagnosis, daily insulin requirement and metabolic control (median HbA1c 8.4% vs 8.8%, respectively, for white Caucasian/SA) Obesity in children No statistically significant differences noted in the rates of overweight or obesity between white Caucasian and SA children at any age grouping. | ||||
| Asmal et al 16 (1981) | South Africa | Cross-sectional analysis |
Ethnicity Two groups: Indians and Black African T1DM Clinic patients who fulfilled the following criteria: age of diagnosis of diabetes <35 years, development of symptoms with/without ketosis in the absence of insulin therapy and duration of diabetes of at least 12 months Method Case records examined, clinical assessments and biochemical tests carried out | Black African: 52 Indians: 38 | Mean age at onset (years) Blacks: 21.8 Indians: 18.0 | 4 weeks |
Basic biochemical data Glucose (mmol/L) Growth hormone (ng/mL) Cortisol (µg/dL) Cholesterol (mmol/L) Triglyceride (mmol/L) Creatinine (µg/dL) Complications Chronic complications associated with microangiopathy were detected in 12 Indians (33%) and 2 blacks (4%). The most common complication was neuropathy found in 19% of Indians with diabetesand in 4% of blacks with diabetes. Two Indians had evidence of diabetic triopathy. |
Indians 15.80±1.50 3.00±0.76 16.20±1.47 5.17±0.32 2.81±0.97 68.90±4.10 |
Black African
14.20±1.50 1.76±0.41 15.80±1.40 4.78±0.26 2.27±0.83 79.40±6.70 | ||
| Ismail et al 14 (2001) | Malaysia | Cross-sectional study |
Ethnicity Three groups: Indians, Malay and Chinese Each ethnic group identified by appearance, language and religion T1DM T1DM defined as acute symptoms associated with heavy ketonuria (>3+) or ketoacidosis at diagnosis, or continuous treatment with insulin within 1 year of diagnosis Method Patients recruited from seven centres throughout Peninsular Malaysia Blood taken for lipid levels, clinical history and physical examination performed | Indians: 154 Malay: 297 Chinese: 128 | Mean age (years) All: 28.8 Indians: 29.1 Chinese: 29.8 Malay: 27.7 | June 1997– June 1998 |
Demographic features BMI (kg/m2) Waist–hip ratio HbA1c (%) Lipid profiles (mmol/L, mean ± SEM) Total cholesterol: Indians (5.74±1.25), Chinese (5.64±1.42), Malay (5.58±1.38) LDL cholesterol: Indians (3.89±1.20), Chinese (3.52±1.22), Malay (3.48±1.12) HDL cholesterol (mean (95% CI)): Indians (1.28 (1.19 to 1.38)), Chinese (1.57 (1.48 to 1.67)), Malay (1.37 (1.28 to 1.46)) Triglycerides (mean (95% C)): Indians (1.02 (0.9 to 1.16)), Chinese (0.82 (0.74 to 0.91)), Malay (1.11 (0.99 to 1.23)) |
Malay (n=297) 26.8±4.9 All: 0.88±0.06 Male: 0.91±0.06 Female: 0.86±0.06 8.8 (8.6–9.1) |
Chinese (n=128) 25.4±4.5 All: 0.88±0.07 Male: 0.90±0.06 Female: 0.85±0.07 8.0 (7.7–8.3) |
Indians (n=154) 25.5±4.3 All: 0.89±0.06 Male: 0.93±0.06 Female: 0.85±0.06 8.5 (8.2–8.8) | |
| Omar et al 13 (1984) | South Africa | Cross-sectional analysis |
Ethnicity Indians and Africans T1DM Classification of diabetes based on criteria by National Diabetes Data Group and WHO Expert Committee Patients with T1DM had always depended on insulin for control of symptoms and prevention of basal ketosis. All patients diagnosed <35 years of age | African T1DM: 86 Indian T1DM: 40 | Mean age of onset (range) African: 23.5 (1–35) years Indians: 17 (1-35) | 2-year period |
Clinical characteristics of patients with T1DM Characteristic Male: female Mean % ideal body weight Mean duration of disease (years) Mean age of onset |
African (n=86) 21: 25 106 (68–153) 3.8 (1–27) 23.5 (1–35) |
Indians (n=40) 17: 24 91 (71–136) 5.4 (1–22) 17 (1–35) | ||
| Papers assessing T1DM complications | |||||||||||
| Swerdlow et al 19 (2004) | UK | Prospective cohort study |
Ethnicity Grouped into SA and non-SA SA identified by computer algorithm (SANGRA) followed by a clerical check by an individual with expertise in this area T1DM Patients with IDDM diagnosed <30 years Method SMRs calculated, comparing mortality in the cohort to the corresponding mortality rates in the general population | Non-SA: 23, 326 SA: 424 | N/A | 1972– 1999 |
Mortality The SMRs for SA patients diagnosed <30 years were 3.9 (95% CI 2.0 to 6.9) in men and 10.1 (95% CI 5.6 to 16.6) in women and in the corresponding non-SA were 2.7 (95% CI 2.6 to 2.9) in men and 4.0 (95% CI 3.6 to 4.3) in women. | ||||
| Mehta et al 11 (2011) | UK | Cross-sectional study |
Ethnicity Ethnicity was categorised as SA or WE based on patient record documentation or by analysis of their name using a validated name recognition software ‘Nam Pechan’ supplemented by a visual inspection of surnames and forenames T1DM Patient coded as having T1DM in the clinical database of a specialist outpatient diabetes clinic in Leicestershire, UK—no diagnostic criteria included Method Patient characteristics and other data were extracted from the clinical workstation, a clinical database of patients attending a specialist outpatient diabetes clinic in Leicestershire | WE: 1169 SA: 163 |
Mean age (years) WE: 45.3 SA: 41.9 | 2003– 2005 |
No of comorbidities (n (%)) 0 1 ≥2 Macrovascular (n (%)) CVD Ischaemic heart disease Peripheral vascular disease Cerebrovascular disease TIA Microvascular (n (%)) Retinopathy Neuropathy Nephropathy Glycaemic control (n (%)) HbA1C <7% HbA1C ≥7% |
SA (N=163) 114 (69.9) 36 (22.1) 13 (8.0) 25 (15.3) 20 (12.3) 3 (1.8) 6 (3.7) 0 63 (38.7) 24 (14.7) 22 (13.5) (N=163) 19 (12.0) 144 (88.0) |
WE (N=1169) 878 (75.1) 235 (20.1) 56 (4.8) 132 (11.3) 97 (8.3) 31 (2.7) 21 (1.8) 2 (0.2) 561 (48.0) 325 (27.8) 118 (10.1) (N=1169) 193 (17.0) 976 (83.0) |
p Value 0.166 0.133 0.093 0.790 0.130 1.000 0.025 <0.001 0.184 0.113 | |
| Sivaprasad et al 18 (2012) | UK | Cross-sectional study |
Ethnicity Self-reported ethnicity based on UK census standard (Census 2001): categorised as ‘White European’, ‘African', ‘South Asian’, ‘Mixed’, ‘other ethnic group’ and ‘not known’ T1DM Patients coded as T1DM in the database of the local DR screening service—no diagnostic criteria included Method To assess ethnic variations of the prevalence of DR and visual impairment in two multiracial cohorts in the UK (Yorkshire and South East London) | WE: 2628 African: 344 SA: 120 | Mean age of T1DM population: 39.4 years | 2008– 2009 |
Ethnic group Any diabetic retinopathy WE African South Asian Any maculopathy (M1) WE African SA CSMO (M1P1) WE African SA STDR (R2 or R3 or M1P1) WE African SA |
Prevalence: n (%) 1446 (55.0) 154 (44.8) 64 (53.3) 371 (14.1) 47 (13.7) 171 (6.5) 17 (14.2) 35 (10.20 12 (10.0) 318 (12.1) 53 (15.4) 19 (15.8) |
Age-standardised prevalence: % (95% CI) 55.0 (53.2 to 56.9) 42.8 (37.3 to 48.3) 54.0 (44.8 to 63.2) 13.1 (9.4 to 16.8) 16.6 (10.0 to 23.2) 6.5 (5.6 to 7.4) 10.0 (6.7 to 13.3) 11.2 (5.4 to 16.9) 12.1 (10.9 to 13.3) 15.9 (11.8 to 20.0) 17.5 (10.6 to 24.3) 14.1 (12.8 to 15.4) | ||
| Thomas et al 15 (2012) | South Africa | Retrospective observational study |
Ethnicity Caucasian, indigenous African, Asian and mixed race T1DM Classified as having T1DM on clinical assessment according to the American Diabetes Association classification of diabetes Method Retinal photography was conducted using a non-mydriatic digital camera without mydriasis and graded by one of three senior graders. | Caucasian: 1247 Indigenous African: 117 Asian: 118 Mixed race: 49 | Mean age (years) Caucasian: 35.7 Indigenous African: 36.3 Asian: 32.2 Mixed race: 32.6 | 2001– 2010 |
DR Caucasian (1247) Indigenous African (117) Asian (118) Mixed race (49) |
Any DR (n=541) Crude OR (95% CI) 1.00 0.71 (0.46 to 1.09) 1.10 (0.74 to 1.63) 1.01 (0.56 to 1.84) |
Adjusted OR (95% CI) 1.00 1.72 (1.00 to 2.97) 2.02 (1.23 to 3.29) 1.29 (0.62 to 2.69) |
RDR (n=142) Crude OR (95% CI) 1.00 0.95 (0.49 to 1.84) 1.05 (0.54 to 2.04) 1.10 (0.42 to 2.88) |
Adjusted OR (95% CI) 1.00 3.40 (1.40 to 8.26) 2.07 (0.90 to 4.75) 1.06 (0.36 to 3.18) |
| Omar et al 17 1984 | South Africa | Crosssectional analysis |
Ethnicity 2 groups: Indians and Black African. T1DM Patients with onset of IDDM <35 years at King Edward Hospital in Durban. Diagnosis of IDDM based on the criteria recommended by WHO. Method Both case records obtained and a physical examination performed to assess complications. | Black African: 92Indians: 41 | Mean age at onset (yrs) Blacks: 17 Indians: 23.5 | Not mentioned |
Complications Keto-acidosis Neuropathy peripheral autonomic Retinopathy Nephropathy Triopathy Ischaemic heart disease Hypertension Cataracts Tuberculosis |
Black African 53 (58%) 20 (22%) 4 (4%) 13 (14%) 3 (3%) 1 (1%) - 4 (4%) 5 (5%) 6 (7%) |
Indians 22 (54%) 13 (32%) 2 (5%) 9 (22%) 3 (7%) 2 (5%) - 2 (5%) 2 (5%) 1 (2%) |
Total 75 (56%) 33 (25%) 6 (5%) 22 (17%) 6 (5%) 3 (2%) - 6 (5%) 7 (5%) 7 (5%) | |
bp, blood pressure; BMI, body mass index; CSMO, clinically significant macular oedema;CVD, cardiovascular disease; DR,diabetic retinopathy; HbA1c, haemoglobin A1c; HDL, high-density lipoprotein;eGFR, estimated glomerular filtration rate; IDDM, insulin-dependent diabetes mellitus; LDL, low-density lipoprotein;M1, maculopathy; NCH, New Cross Hospital;P1, macular laser;QEH, Queen Elizabeth Hospital; R1, mild to moderate non-proliferative diabetic retinopathy; R2, preproliferative diabetic retinopathy; R3, proliferative diabetic retinopathy; SA, South Asian; SANGRA, South Asian Names and Group Recognition Algorithm;SMR, standardised mortality ratio;STDR,sight-threatening diabetic retinopathy; T1DM, type 1 diabetes mellitus; TIA, transient ischaemic attack; WE, white European.
*p Value <0.05.