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Stephanie Knox (now at CHERE) Helena Britt Christopher Harrison

A BEACH SAND study Estimated prevalence of chronic illnesses (identified as Health Priority Areas) among general practice patients. Stephanie Knox (now at CHERE) Helena Britt Christopher Harrison Australian GP Statistics & Classification Centre

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Stephanie Knox (now at CHERE) Helena Britt Christopher Harrison

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  1. A BEACH SAND studyEstimated prevalence of chronic illnesses (identified as Health Priority Areas) among general practice patients Stephanie Knox(now at CHERE) Helena Britt Christopher Harrison Australian GP Statistics & Classification Centre A collaborating Unit of the Australian Institute of Health and Welfare & the University of Sydney A collaborating unit of the Australian Institute of Health and Welfare and the University of Sydney

  2. Today’s aims • About us • BEACH methods • Representativeness • Some changes in morbidity managed by GPs • SAND sub-studies – methods • Results of the prevalance study Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  3. The Family Medicine Research Centre • A University of Sydney Research Centre academically attached to the Department of General Practice & School of Public Health • A Collaborating Centre of the World Organization of Family Doctors (Wonca) • All moneys are self-generated through competitive grants, consultancies and contracts. • Our work is health services research and development. • The Australian GP Statistics & Classification Centre • A collaborating unit of the Australian Institute of Health and Welfare and the University of Sydney, within the FMRC. • Responsible for the BEACH program which is conducted under the AIHW Act, with Ethics approval from the University and AIHW Ethics Committees Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  4. BEACH • Began April 1, 1998 • Now in its 10th year (April 1, 2007) • ~9,000 participants • Representing 7,500+ GPs • >40% of recognised GPs) • Data available ~ 900,000 encounters • Data being used by the profession, researchers, governments & industry Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  5. BEACH Aims • to provide a reliable and valid continuous national data source of timely GP–patient encounter information • to inform the community of the care provided to the vast majority of the population by GPs - the gate keepers of our medical system • to assess patient health risk factors, prevalence of disease, or longer term management--on selected subjects in sub-samples of patients- up to 20 sub-studies per year (SAND- Supplementary Analysis of Nominated Data) Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  6. BEACH methods • A cross sectional encounter based study • Paper based data collection • National GP random sample (drawn by DoHA) • 1,000 GPs per year • 20 per week x 50 weeks a year - ever changing • 100 consecutive encounters per GP • All types of encounters included • National data for 100,000 encounters p.a. Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  7. Post-stratification weights • To ensure national representation of GP encounters, each year the data are weighted 1. To correct for the under-representation of young GPs <35 years (small but important) 2. To give more weighting to the encounters of busy GPs and less to (e.g.) part-time GPs data are weighted by HIC A1 Medicare claims previous quarter. Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  8. Observed vs expected age distribution by state Expected = MBS (A1) claims, observed = BEACH sample Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  9. Observed vs expected age distribution by state Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  10. Observed vs expected age distribution by state Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  11. BEACHvariables (see recording form) • G.P characteristics(GP completed questionnaire) • Practice characteristics (GP completed questionnaire) • Patient characteristics • Encounter details • Patient reasons for encounter (up to 3) • Problems managed (up to 4) Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  12. BEACHvariables • Management (of each problem) • Medications prescribed, supplied, advised (up to 4/problem) • Non-pharmacological treatments (up to 2/problem) • Clinical treatments • Therapeutic procedures • New referrals & admissions (up to 2 – linked to problem(s)) • Pathology tests ordered (up to 5–each linked to problem(s)) • Imaging & other tests ordered (up to 2 - linked) (view form) Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  13. G.P Characteristics • age • sex • country of graduation • years in general practice • FRACGP • currently in training program • practice location (State,RRMA, ARIA, SEIFA) • practice size • use of computers • + other variables over the years Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  14. Patient characteristics • Age (from DoB) • Sex • Status to the practice (new/seen before) • NESB (Yes/no) • Aboriginal (self ID – Yes/no) • Torres Straight Islander (self ID – Yes/no) • Health care card holder (Yes/no) • VA card holder (yes/no) • Reasons for encounter (up to 3) Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  15. Some changes over time A quick look at: • patients seen • problems managed Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  16. Age of patients at encounter changing over time (% of workload) Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  17. Summary of problems over time Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  18. Selected morbidity management rates over time - rate per 100 encounters Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  19. Other problems managed over time rate per 100 encounters Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  20. Encounter data • Tells us about: • patient demand for care • the problems managed • How specific problems are managed by GPs • It does NOT provide prevalence estimates of disease: • among the attending population (attendance gives  chance of selection) • among the population at large Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  21. SAND: Supplementary Analysis of Nominated Data “The bit on the bottom of the form” • Questions usually asked of the patient • Each GP pack divided into three: 40 + 30 + 30 • 40 BMI, smoking status, alcohol intake • 30 nominated subject 1 • 30 nominated subject 2 • Nominated subject 5 weeks -- 3000 random sample Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  22. Available through http://www.fmrc.org.au (go to ‘BEACH’ and select ‘publications’) Also see ‘Abstracts’ in the publication section of our website Hard copies of reports from http://www.aihw.gov.au (cost $15-27 each book in GEP series) AGPSCC Phone +61 2 9845 8151 email: gpstats@fmrc.org.au A collaborating unit of the Australian Institute of Health and Welfare and the University of Sydney

  23. Population prevalence of disease • Important for health policy and health service planning • In Australia usually rely on results from the National Health Survey (NHS) (conducted by the ABS) • NHS estimates population prevalence based on patient self-reported morbidity • Using structured interview, with trained interviewer, in respondent’s home to elicit health-related information Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  24. National Health Survey • Advantages: • includes a representative sample of the total population (n = about 27,000 in 2004) • Shortcomings: • Only conducted every 3 years ( 4 in the past) • Self-report likely to be unreliable (lack of clinical knowledge, recall issues etc) Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  25. The international scene • Most countries rely on similar national surveys • Many people question the reliability of such estimates • Some studies suggest patient recall of morbidity better for well defined conditions (e.g. Diabetes, heart disease) than for ill-defined conditions (e.g. back pain) • Accuracy of household health data tested by Moore (US) in 1972, on chronic disease prevalence • One third reported 1+ chronic disease (n=333) • 106 medical records checked • False positive chronic disease identification by patient self report = 25%; false negative 38% Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  26. Prevalence data from EHRs? • Some have tried to produce prevalence estimates from GP EHRs • This works better in countries with patient registers than in fee for service system. • Major issue is incompleteness of record • Some question why we need to sample people who do not utilise the health care system (i.e. currently not a cost) Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  27. Our study Aims: to use an ongoing national survey of GP activity to provide estimates of the prevalence of diagnosed morbidity among the population of general practice patientsin Australia. Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  28. Methods • A SAND (Supplementary Analysis of Nominated data) substudy in the BEACH program • ‘the bit on the bottom of the form’ • BEACH GPs 12/07/05-19/08/05 & 25/10/05-28/11/05 • Each GP asked, for 30 consecutive patients ‘Does this patient have any of the following conditions which require ongoing management?’ • Final sample 9156 from 305 GPs Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  29. Conditions listed on the formTick boxes provided, multiple response allowed • Psychological problems --Depression --Anxiety --Insomnia --Other psychological problem • Other problems --Hyperlipidaemia --Chronic back pain --Malignant neoplasms --Gastro-oesophageal reflux disease • Respiratory problems --Asthma -- mild --moderate --severe --Chronic obstructive airways disease • None of these conditions. • Cardiovascular disease --Ischaemic heart disease --Cerebrovascular disease --Peripheral vascular disease --Congestive heart failure --Hypertension – complicated --Hypertension – uncomplicated --Other • Arthritis --Osteoarthritis --Rheumatoid arthritis --Other arthritis • Diabetes --Type 1 --Type 2 --Other Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  30. Prevalence among whom? • Patient sample drawn at point of GP-patient encounters is biased towards frequent attenders, who are older and have more health problems than population as a whole. • Sample will over-estimate prevalence of health conditions in the total patient population Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  31. Adjust to patient population • Enumerate the proportion of the sampled general practice patients who have a chronic condition requiring ongoing management • Use these crude sample rates to estimate prevalence in the population of patients attending GPs at least once, by adjusting for annual visit rates. Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  32. Methods (cont.) • Crude rates calculated (% with the disease) • Crude rate weighted by visit frequency related to age and sex, by weighting SAND sample against age-sex distribution of population who visited a GP (1+ times) in 12 months (April 2004-March 2005) • Used SAS V9.13 to adjust for the cluster design of the study. Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  33. The underlying theory • Recording of morbidity present in the patient will be more reliable with the combined input of: • the patient, • the GP, and • the medical record (where available) than patient self-report alone. Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  34. Results – Age-sex distribution c/f population attending GP N = 9,156 patients from 305 participating GPs. Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  35. Prevalence – crude rates (what’s in the waiting room) Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  36. Per cent of attending patients Prevalence – crude rates Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  37. Prevalence – crude rates Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  38. Prevalence – crude rates Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  39. Per cent of attending patients Prevalence – crude rates Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  40. Prevalence – crude rates + adjusted Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  41. Prevalence – crude rates + adjusted Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  42. Prevalence – crude rates + adjusted Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  43. Prevalence – crude rates + adjusted Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  44. Est prevalence in GP patient pop’n c.f. population prevalence (NHS 2004) Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  45. Est prevalence in GP patient pop’n c.f. population prevalence (NHS 2004) Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  46. Est prevalence in GP patient pop’n c.f. population prevalence (NHS 2004) Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  47. What about population prevalence? • If we assume that all of the 15% who did not attend a GP in 2005 have none of the listed diseases under management,we have to add these into the denominator, to gain an estimate of prevalence among the total population Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  48. Prevalence in patient population –extrapolated to total population c.f. NHS Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

  49. Discussion • Differences in question • SAND ‘ongoing management’ vs NHS present/absent • SAND Chronic back pain vs back pain • Methods seem appropriate – supported by decrease population estimate for prevalence of Asthma to LESS than the NHS – this suggests that the assumption of no attendance = no disease does not apply to asthma. • Certainly the costs of collection are marginal c.f. NHS Estimated prevalence of NHPA morbidities. SPH Seminar August 2007

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