Using NAMCS and NHAMCS Data

1. Using NAMCS and NHAMCS Data Linda McCaig and David Woodwell Ambulatory Care Statistics Branch Division of Health Care Statistics National Center for Health Statistics/CDC

2. Overview • Background • Data uses • Survey methodology • Current and proposed survey items • User considerations • Methodological studies • Data dissemination • NCHS Research Data Center

4. National probability sample surveys • National Ambulatory Medical Care Survey (NAMCS) • Patient visits to non-federal office-based physicians • National Hospital Ambulatory Medical Care Survey (NHAMCS) • Patient visits to EDs and OPDs of non-federal short-stay hospitals

5. Original NAMCS survey goals • National statistics • Professional education • Health policy formulation • Medical practice management • Quality assurance

6. NAMCS history • Survey began in 1973 • Annual data collection through 1981 (NORC) • Conducted in 1985 (NORC) • Annual began again in 1989(Census)

7. NHAMCS history • Survey began in 1992 • Annual data collection (Census)

8. How are NAMCS and NHAMCS data used?

9. Data uses • To understand health care practice and find inequities • To track certain conditions • To establish national priorities • To serve as comparison points for states • To measure Healthy People objectives

10. Data users • Over 100 journal publications in last 2 years • Medical associations • Government agencies • Health services researchers • University and medical schools • Broadcast and print media

11. Setting government policy • ED as a “safety net” for the uninsured • Development of the Resource-Based Relative Value Scale (RBRVS)

13. Antibiotic prescribing rates at physician office visits for children Rate per 1000 population Rate per 1000 visits

15. Prescribing rates at physician office visits by specialty Psychiatry Ophthalmology Otolaryngology Orthopedic surgery

16. Female ambulatory care visit rates for selected diagnoses by race

17. Annual rate of illness and injury ED visits for seniors by race Illness, black1 Illness, white 1 Injury, black 1 Injury, white NOTE: 1 p < .01.

18. Diabetes visit rates per 10,000 persons by setting

19. NAMCS and NHAMCS Methodology

20. NAMCS Scope • Includes non-federal, office-based physicians • Excludes physicians whose main activity is teaching, research, administration, hospital-based care, or who are unclassified as to activity and those in the certain specialties

21. In-Scope NAMCS locations • Freestanding clinic/urgicenter • Federally qualified health center • Neighborhood and mental health centers • Non-federal government clinic • Family planning clinic • Health maintenance organization • Faculty practice plan • Private solo or group practice

22. Out-of-Scope NAMCS locations • Hospital ED’s and OPD’s • Ambulatory surgicenter • Institutional setting (schools, prisons) • Industrial outpatient facility • Federal Government operated clinic • Laser vision surgery

23. 112 NHIS PSUs 3,000 physicians 25,000 visits 1 week reporting period NAMCS Sample design

24. NHAMCS Scope • OPD was intended to be parallel to the NAMCS in the hospital setting • General medicine, surgery, pediatrics, ob/gyn, substance abuse, and “other” clinics are in-scope • Ancillary services are out of scope

25. 112 NHIS PSUs 500 hospitals 400 EDs and 250 OPDs 24,000 ED visits and 30,000 OPD visits 4-week reporting period NHAMCS Sample design

26. Gaining cooperation • Advance letters • Endorsement letters • Public relations materials • Conversion of refusal

27. Data collection procedures • Induction visit by Census field representative (FR) • FR training of office/hospital staff • Random start number • Take every number • Prospective or retrospective method

28. Items collected • Patient characteristics • age, race, sex • Visit characteristics • Reason for visit, diagnosis, medication • Provider characteristics • physician specialty, hospital ownership

29. Repeating fields • Reason for visit (3) • Cause of injury (3) • Diagnosis (3) • Ambulatory surgical procedures (2) • Medications (6)

30. Data processing • Data are coded and keyed by Analytical Sciences Inc. (ASI) • Quality control procedures • Edit checks by NCHS

31. Coding systems used • A Reason for Visit Classification (NCHS) • ICD-9-CM • Drug coding classification system (NCHS) • National Drug Code Directory

32. NAMCS and NHAMCS 1999-2000 PRFs

33. Patient record form - common items • Patient’s zip code • Date of visit • Date of birth • Sex • Ethnicity

34. Patient record form- common items • Race • Source of payment • HMO status • Reason for visit

35. Patient record form –common items • Diagnosis • Diagnostic/screening services • Medications • Providers seen • Visit disposition

36. Injury items • External cause – narrative text since 1997 • Place of injury • Work related injury • Intent

37. Office and OPD PRF- unique items • Was patient referred for visit • Patient’s primary care physician • Patient seen before • Major reason for visit

38. Office and OPD PRF- unique items • Ambulatory surgical procedures • Therapeutic and preventive services • Time spent with physician (NAMCS only)

39. ED Patient record form- unique items • Arrival time • Discharge time • Immediacy • Presenting level of pain • Procedures

40. NAMCS and NHAMCS PRF revisions 2001-02 – emphasis on the continuity of care

41. Office and OPD PRF - new items for 2001-02 • How many visits in last 12 months • Initial or follow-up visit • Do other physicians share care • Total number of medications

42. ED PRF- new items for 2001-02 • Discharge time • Visit related to alcohol use • Patient seen in last 72 hours • Initial or follow-up visit • Visit related to adverse drug event • Initial vital signs • Total number of medications

43. NAMCS and NHAMCS PRF revisions 2003-04

44. New oriented X 3 is visit work related list up to 8 medications Recycled mode of arrival presenting level of pain time seen by physician ED PRF- revisions for 2003-04

45. 2001-02 Induction Interview revisions • NAMCS – e.g., electronic medical records, number of managed care contracts • NHAMCS – e.g., Pediatric Emergency Services and Equipment Supplement (HRSA)

46. 2003-04 Induction Interview revisions • NAMCS – e.g., Physician was a member of a practice-based research network (PBRN) • NHAMCS – e.g., Daily census of occupied and available beds

47. ED Overcrowding • Physician coverage hours • Log of ambulance diversion

48. Analysis of Facility Level Data

49. Percent of physicians who do not accept new patients by payment type

50. Distribution of hospital EDs on average waiting time