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Table 4 Studies of frequency of atrial fibrillation in clinical groups

From: Atrial fibrillation in the Indigenous populations of Australia, Canada, New Zealand, and the United States: a systematic scoping review

Author (Year) Publication type Country Indigenous population Calendar period Methods Key findings on Indigenous AF Quality score (Newcastle-Ottawa Scale applied only to Indigenous AF data) Comments
(a) Frequency of atrial fibrillation in primary care consultations
Title: Aboriginal and Torres Strait Islander Health Performance Framework 2012 - Detailed Analyses
Australian Institute of Health and Welfare (2013) [40] Report Country: Australia Design: Cross-sectional Age-standardised rate (no. of encounters per 1,000 in which AF managed): Indigenous: 15.1 (CI 5.7-24.4) Other: 11.5 (CI 11.0-12.0) Rate ratio 1.3 (NS) Rate difference 3.5 (NS) NOS (adapted for cross-sectional): 5/10
  Pop: Aboriginal Data Source: BEACH (written questionnaire, random sample of GPs across Australia)   Likely under-identification of Indigenous patients
  Period: 2006–07 to 2011-12 Setting: General practice attendances   
   Sample size: AF managed during 38 ‘Indigenous’ and 5548 ‘Other’ GP attendances   
(b) Frequency of atrial fibrillation in hospital admissions
Title: Atrial fibrillation in Indigenous and non-Indigenous Australians: a cross-sectional study
Wong (2014) [29] Conference abstract later published as a journal article Country: Australia Design: Retrospective cross-sectional study Indigenous vs non-Indigenous frequency of AF adjusted for age, sex & CVD comorbidity (odds ratio): 1.183 (CI 0.977-1.432; p = 0.085) NOS (adapted for cross-sectional): 5/10 Unclear definition of AF occurrence (throughout series of ≥1 potential admission per patient) No ‘lookback’ to establish age at 1st AF admission Representativeness of population uncertain from single institution Denominator for comparisons unclear
  Pop: Indigenous Australians (IA) Data Source: Administrative data Crude age-stratified frequency of AF Indigenous vs non-Indigenous: <60 yrs 2.57 vs 1.73 % p < 0.0001 ≥ 60 yrs 4.61 vs 9.26 % p < 0.0001  
  Period: 2000-2009 Setting: Single tertiary hospital (South Australia) Average age of patients with AF (years): Indigenous 55.4 (SD 13.2) vs Non-Indigenous 74.5 (SD 13.1) p < 0.001  
   Sample size: 204668 persons admitted (5892 Indigenous [3.6 %]) 14373 patients with AF diagnosis (221 Indigenous)   
(c) Frequency of atrial fibrillation in specific diagnostic groups
i. Heart failure
Title: Incidence of first heart failure hospitalisation and mortality in Aboriginal and non-Aboriginal patients in Western Australia, 2000-2009
Teng (2014) [44] Journal article Country: Australia Design: baseline descriptive (within cohort study) hospitalised HF patients Crude AF prevalence significantly higher in non-Aboriginal patients: 20–55 years NOS (adapted for cross-sectional): 9/10 15-year clearance period to identify first HF admission; codes validated; 5-year look back for history of AF
  Pop: Aboriginal Data Source: Linked hospital and death records Aboriginal = 17.2 % Non-Aboriginal = 26.6 % p < 0.001 55–84 years  
  Period: 2000-2009 Setting: Hospital Aboriginal = 24.6 %% Non-Aboriginal = 44.9 % p < 0.001  
   Sample size: 1013 Aboriginal and 16,366 non-Aboriginal hospitalised HF patients   
Title: Mortality outcomes among status Aboriginals and Whites with Heart Failure
Lyons (2014) [43] Journal article Country: Alberta, Canada Design: baseline descriptive (within cohort study) Crude prevalence of AF (as comorbidity): Aboriginals (18 %); Whites (34 %) NOS (adapted for cross-sectional): 8/10 Albertan Aboriginal population comprises 52 % First Nations, 45 % Métis & 3 % Inuit. Identification of Indigenous status in study based on registration—only First Nations are eligible, of whom 81 % are registered. Métis classified as White in this study.
  Pop: Aboriginal Data Source: Health care administrative (HMD, ED, ambulatory care) databases linked to the insurance registry (with ethnicity recorded)   
  Period: 2000-2008 Setting: Hospital   
   Sample size: 42,288 whites, 1158 Aboriginals   
ii. Ischaemic heart disease
Title: Ischaemic heart disease in New Zealand Māori and non-Māori: an age adjusted incidence in hospitalised patients over 10 years with emphasis on clinical features in the Māori
Dancaster (1982) [45] Journal article Country: NZ Design: Descriptive AF detected in 39 % of Māori versus 6 % of non-Māori cases NOS (adapted for cross-sectional): 3/10 No statistical inference data given for AF proportions Old study—contemporary relevance uncertain
  Pop: Māori Data Source: Hospital records   
  Period: 1971-1980 Setting: Single regional hospital CCU   
   Sample size: 887 CCU-admitted IHD cases   
iii. Renal failure
Title: Atrial fibrillation in haemodialysis patients: do the guidelines for anticoagulation apply?
To (2007) [48] Journal article Country: NZ Design: baseline descriptive (within cohort study) Data Source: Subjects identified from identified from ANZ Dialysis and Transplant Registry; Hospital records—30 month follow-up Crude percentage AF: Caucasians 32.8 % Māori 28.6 % Pacific Islanders 19.6 % Asians 16.7 % NOS (adapted for cross-sectional): 6/10 Underpowered, therefore essentially descriptive study of AF prevalence
  Pop: Māori Setting: Single hospital haemodialysis unit   
  Period: 2003 Sample size: 155 haemodialysis patients; 28 (18 %) Māori, 51 (33 %) Pacific Islander   
Title: Trends in the incidence of atrial fibrillation in older patients initiating dialysis in the United States
Goldstein (2012) [47] Journal article Country: US Design: Cohort study Crude incidence rate: 148/1000 person-years Compared to non-Hispanic whites, Blacks (−30 %), Asians (−29 %) & Native Americans have lower risk (−42 %) of incident AFCrude incidence rate: 148/1000 person-years Compared to non-Hispanic whites, Blacks (−30 %), Asians (−29 %) & Native Americans have lower risk (−42 %) of incident AF NOS (cohort): 9/9 Small sample size for Native Americans (1 %).
  Pop: Native Americans Data Source: US Renal Data System   
  Period: 1995-2007 Setting: Population-based (older Medicare beneficiaries)   
   Sample size: 258,605 (1 % Native Americans)   
Title: The increasing prevalence of atrial fibrillation among hemodialysis patients
Winkelmayer (2011) [46] Journal article Country: US Design: series of cross-sectional surveys Native American HD patients univariate RR for AF 0.38 (vs Causasian); adjusted RR 0.53 (CI 0.50-0.57) NOS (adapted for cross-sectional): 10/10
  Pop: Native American Data Source: United States Renal Data System   
  Period: 1992-2006 Setting: maintenance hemodialysis pts—whole of USA   
   Sample size: >105 pts each year of study   
iv. Stroke
Title: Prevalence of stroke and coexistent conditions: disparities between Indigenous and non-Indigenous Western Australians
Katzenellenbogen (2014) [49] Journal article Country: Australia Design: baseline descriptive (within cohort study) AF more prevalent in Aboriginal than other stroke cases in all age groups <70 years. Crude AF rates were 20 % less in Aboriginal patients due to differing age distributions. NOS (adapted for cross-sectional): 7/10 (AF not focus of study) Long (20-year) look-back period to identify stroke and AF; AF codes not validated; no stroke type data
  Pop: Aboriginal Data Source: Linked hospital and death records   
  Period: 2007-2011 Setting: Hospital   
   Sample size: Average 13,591 patients per year (5 % Aboriginal)   
Title: Racial disparities among Native Hawaiians and Pacific Islanders with intracerebral hemorrhage
Nakagawa (2012) [50] Journal article Country: Hawaii, US Design: Cross-sectional Crude prevalence of AF: No significant difference between whites & NHPI (10 % vs 17 %) NOS (adapted for cross-sectional): 7/10
  Pop: Native Hawaiians & Pacific Islander (NHPI) Data Source: Clinical database   Single-centre (referral bias). Good clinical data. Limited analysis, given small sample size
  Period: 2004-2010 Setting: Hospital admissions from single tertiary hospital   
   Sample size: 562 ICH cases   
Title: Disparities among Asians and native Hawaiians and Pacific Islanders with ischemic stroke
Nakagawa (2013) [51] Journal article Country: Hawaii, USA Design: Cross-sectional AF prevalence: No significant difference between whites & NHPI Crude prevalence 15 % vs 19 % Adjusted OR 1.06 (0.64-1.75) NOS (adapted for cross-sectional): 8/10 Single-centre (referral bias). Good clinical data.
  Pop: NHPI Data Source: Clinical database   
  Period: 2004-2010 Setting: Hospital admissions from single tertiary hospital   
   Sample size: 1,921 ischaemic strokes   
v. Rheumatic heart disease
Title: Percutaneous balloon mitral commissurotomy in Indigenous versus non-Indigenous Australians
McCann (2008) [52] Journal article Country: Australia Design: baseline descriptive (within cohort study) Crude AF prevalence: non-significantly lower in Indigenous Australians (44 % vs 29 %) NOS (adapted for cross-sectional): 7/10 Only 36 (11 %) of Indigenous Australians. Age-adjusted survival was worse in Indigenous Australians.
  Pop: Indigenous Australians Data Source: Clinical database   
  Period: 1990-2006 Setting: two tertiary hospitals   
   Sample size: 327   
Title: A review of valve surgery for rheumatic heart disease in Australia
Russell (2014) [53] Journal article Country: Australia Design: Cross-sectional Crude frequency of perioperative AF (%): Indigenous 33.3 Non-Indigenous 41.6 (p = 0.039) n.b., difference in mean age: Indigenous 37.4 years Non-Indigenous 65.1 year NOS: N/A (descriptive study) Comparison of crude frequencies of AF in the two ethnic categories is markedly confounded by age disparity
  Pop: Aboriginal & Torres Strait Islander Data Source: National Cardiac Surgery Database   
  Period: 2001-2012 Setting: Hospitalised surgery patients   
   Sample size: 1384 RHD (174 Indigenous) compared with 15843 non-RHD valvular surgery patients   
vi. Other cardiac surgery
Title: Incidence, secular trends, and outcomes of cardiac surgery in Aboriginal peoples
Sood (2013) [54] Journal article Country: Canada Design: baseline descriptive (within cohort study) No significant difference in AF prevalence at baseline (10.1 % non-Aboriginal v 12.0 % Aboriginal) NOS (cohort): 9/9 Main aims were to compare Aboriginal vs non-Aboriginal patients for incidence, secular trends & outcomes of cardiac surgery. Limited info on AF: crude baseline prevalence in a cohort with known selection bias (demonstrated disparity in selection for surgery)
  Pop: Canadian Aboriginal Data Source: Provincial Cardiac Surgery registry   
  Period: 1995-2007 Setting: Whole of Manitoba   
  Age: >15 years Sample size: 12170 (Aboriginal 574; 4.7 %)   
vii. Paediatric patients
Title: Excellent cardiac surgical outcomes in paediatric indigenous patients, but follow-up difficulties
Rohde (2010) [55] Journal article Country: Brisbane, AUS Design: Retrospective review New atrial arrhythmia as post-surgical complication: 2.4 % NOS (adapted for cross-sectional): 7/10 Atrial arrhythymia was one endpoint (complication) of follow-up after cardiac surgery.
  Pop: Indigenous Australians (paediatric) Data Source: Cardiothoracic database, chart review   
  Period: 2002-2009 Setting: Single tertiary hospital   
   Sample size: 112 cases (123 operations)   
Title: Preoperative risk factors for long-term survival following cardiac surgery for rheumatic heart disease in the young
Remenyi (2012) [56] Conference abstract Country: Auckland, NZ Design: Retrospective cohort study Pre-operative AF independently predicted mortality in multivariate analysis (HR 5.2, p < 0.01) NOS: N/A (abstract) No Causasian comparison group
  Pop: Māori & PI Data Source: Cardiothoracic database, chart review   
  Period: 1990-2006 Setting: Single tertiary hospital   
   Sample size: 212 cases   
  1. BEACH Bettering the Evaluation and Care of Health survey, GP general practitioner, NOS Newcastle-Ottawa Scale, AF atrial fibrillation, CVD cardiovascular disease, SD standard deviation, HF heart failure, HMD Hospital Morbidity Database, ED emergency department, NZ New Zealand, CCU coronary care unit, IHD ischaemic heart disease, ANZ Australia & New Zealand, HD haemodialysis, RR relative risk, NHPI Native Hawaiian & Pacific Islander, N/Anot applicable, HR hazard ratio, PI Pacific Islander