Mental Health Data from the NAMCS and NHAMCS Susan M. Schappert, M.A. Ambulatory and Hospital Care Statistics Branch Division of Health Care Statistics

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Mental Health Data from the NAMCS and
NHAMCSSusan M. Schappert, M.A.Ambulatory and
Hospital Care Statistics BranchDivision of
Health Care Statistics
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Topics To Be Covered

• Survey Overview
• Data Collected
• Published Mental Health Research Using Data from
  NAMCS and NHAMCS
• User Considerations
• How to Get the Data

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An Overview of NAMCS and NHAMCS
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NAMCS and NHAMCS

• National Ambulatory Medical Care Survey (NAMCS)
• Visits to office-based physicians
• National Hospital Ambulatory Medical Care Survey
  (NHAMCS)
• Visits to hospital emergency and outpatient
  departments (EDs and OPDs)

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History of NAMCS

• Planning began in 1967
• Inaugurated in 1973
• Fielded 1973-1981, 1985, 1989-present
• Database covering more than 30 years

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History of NHAMCS

• Planning began in 1976
• Inaugurated December 1991
• Fielded annually
• 17th year of operation

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NAMCS Sample Design

• Three stage design
• 112 primary sampling units (counties/groups of
  counties)
• Physician practices within PSUs
• Patient visits within practices
• About 3,000 physicians are selected
• Each physician is randomly assigned to a
  1-week reporting period
• Data obtained for 25,000-30,000 patient visits
• Sample data must be weighted to produce national
  estimates

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Scope of the NAMCS

• Basic unit of sampling is the physician-patient
  visit
• In scope visits
• Must occur in physicians office
• Must be for medical purposes
• Administrative visits not sampled
• House calls, emails, phone calls not sampled

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Scope of the NAMCS

• Physicians must be
• Classified by AMA or AOA as primarily engaged in
  office-based patient care
• nonfederally employed
• not in anesthesiology, radiology, or pathology
• 59 percent response rate in 2006

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Physicians Sampled in the NAMCS

• Physicians are typically stratified into 15
  specialty groups
• general and family practice, internal medicine,
  pediatrics, ob-gyn, general surgery, orthopedic
  surgery, cardiovascular diseases, dermatology,
  urology, psychiatry, neurology, ophthalmology,
  otolaryngology, and an other category
• 2006 included an additional sample of
  oncologists, and a sample of community health
  centers
• 29,392 Patient Record Forms completed by about
  1,400 physicians in 2006
• 570 primary care physicians (general and family
  practice, internal medicine, pediatrics, and
  ob-gyn) responded in 2006 with data on about
  14,400 visits (nearly half of total visit
  records)
• 80 psychiatrists reported on nearly 1,400 visits
  (4.7 of total)

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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

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Out-of-Scope NAMCS Locations

• Hospital EDs and OPDs
• Ambulatory surgicenter
• Institutional setting (schools, prisons)
• Industrial outpatient facility
• Federal Government operated clinic
• Laser vision surgery

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NHAMCS Sample Design

• Multistage probability design
• First stage sample of 112 PSUs
• Hospitals within PSUs
• Clinics within OPDs, ESA (emergency service area)
  within EDs
• Patient visits within clinics, ESAs
• 4-week reporting period
• 486 hospitals sampled in 2006 35,849 ED visits
  and 35,105 OPD visits

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Scope of the NHAMCS

• Basic unit of sampling is patient visit
• Emergency and outpatient departments of
  noninstitutional general and short-stay hospitals
• Not Federal, military, or Veterans Administration
  facilities
• Located in 50 states and D.C.

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Sampled OPD Clinics

• 6 clinic types are defined and used for sampling
  general medicine, surgery, pediatrics, ob-gyn,
  substance abuse, and other
• Other includes anxiety, behavioral medicine,
  eating disorders, psychiatry (adult, child,
  pediatric, geriatric), mental health, mental
  hygiene, psychopharmacology, and sleep disorders
• Not included partial hospitalization programs,
  day hospital programs, psychology, methadone
  maintenance

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Data Collected in the NAMCS and NHAMCS
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Data Collection

• U.S. Census Bureau is our field agent
• Induction interview to train medical office or
  hospital staff on data collection procedures and
  to obtain data on practice or facility
  characteristics
• Physicians office/hospital staff is responsible
  for completion of Patient Record forms Census
  abstracts as a last resort. In 2006, more than
  one-third of NHAMCS forms and about one-half of
  NAMCS forms were completed by Census abstraction.

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Data Collection

• Patient Record Forms (PRFs)
• Nearly identical for NAMCS and OPD
• Some differences for ED
• Redesigned once every 2 years
• Copies at our website www.cdc.gov/nhcs/namcs.htm

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Data Items

• Patient characteristics
• Age, sex, race, ethnicity
• Visit characteristics
• Source of payment, continuity of care, reason for
  visit, diagnosis, treatment
• Provider characteristics
• Physician specialty, hospital ownership, region
  and urban-rural status, use of electronic medical
  records, and much more
• Drug characteristics added in 1980

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Mental Health Items Collected inNAMCS and
NHAMCS-OPD

• Patients reason for visit (all survey years)
• Physicians diagnosis (all survey years)
• Does patient now have depression? (1991-92,
  1995-96, 2005-06)
• Cause of injury (1995-2004), verbatim text added
  (1997-2004)
• Diagnostic/screening services ordered or provided
• Mental status exam (1979-81, 1991-92, 1995-96)
• Depression screening (2005-06)
• Medication therapy (1980-2006)
• Non-medication therapy ordered or provided
• Psychotherapy/therapeutic listening (1973-1981)
• Psychotherapy (1985-92, 1995-2006)
• Psycho-pharmacotherapy (1997-2000)
• Alcohol abuse counseling (1991-92)
• Drug abuse counseling (1991-92)
• Stress management counseling (1991-92, 1997-2000,
  2005-06)
• Mental health counseling (1995-2000)
• Mental health/stress management counseling
  (2001-04)
• Other mental health counseling (2005-06)

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Mental Health Items Collected inNHAMCS-ED

• Patients reason for visit (all survey years),
  verbatim text added 2005-06
• Physicians diagnosis (all survey years)
• Does patient now have depression? (1995-96)
• Cause of injury (1995-2006), verbatim text added
  (1997-2006)
• Intentional injury? (1997-2006)
• Violence-related injury? (1995-96)
• Alcohol- or drug-related visit? (1992-96)
• Alcohol-related visit? (2001-04)
• Adverse drug event (2001-02)
• Patient oriented x 3 (2003-06)
• Medication therapy (all survey years)

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Multiple Response Fields

• Up to 3 reasons for visit, causes of injury,
  physician diagnoses can be reported for each
  visit (no cause of injury on NAMCS and OPD
  starting in 2005)
• Up to 8 medications and each medication can have
  up to 3 therapeutic classes and up to 5
  ingredients
• Multiple procedure codes for NAMCS and OPD

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Coding Systems Used

• Reason for Visit Classification (NCHS)
• ICD-9-CM for diagnoses, causes of injury, and
  procedures
• Drug Classification System (NCHS)
• Multum Lexicon starting with 2006 data
  (previously used National Drug Code Directory)

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Drug Data in NAMCS/ NHAMCS

• Respondents may list up to 8 medications
  (including Rx, or prescription, and OTC, or
  over-the-counter, medications, immunizations,
  allergy shots, anesthetics, and dietary
  supplements) that were ordered, supplied,
  administered, or continued during the visit.
• Each entry is called a drug mention. Visits
  with one or more drug mentions are called drug
  visits.
• Respondents are asked to report trade names or
  generic names only (not dosage, administration,
  or regimen). Cannot link drugs with diagnosis.
  

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• NAMCS or NHAMCS drug data can be analyzed
• at the visit level (for example, the number of
  visits at which a particular drug was prescribed)
• or at the medication level (for example, the
  number of mentions of a particular drug at
  ambulatory care visits

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Published Mental Health Research Using Data from
NAMCS and NHAMCS
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Hot Topics

• See the NAMCS/NHAMCS website for a complete list
  of publications (including journal articles) by
  NCHS and others that use our data (about 100
  focus on mental health) updated monthly
• Mental health research using NAMCS/NHAMCS data
  includes
• visits for specific diagnoses (depression, ADHD
  attention deficit/hyperactivity disorder, and
  sleep disorders have been most commonly
  published, but there are also studies on visits
  for anxiety disorders, bipolar disorder, autism,
  schizophrenia)
• pharmacotherapy (antidepressants, antipsychotics,
  hypnotics, stimulants, psychotropics in general)
• mental health care by physicians other than
  psychiatrists
• racial/ethnic/gender disparities in mental health
  care
• other topics such as self-harm (ED visits),
  insurance issues, substance abuse

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Additional Mental Health Data from NAMCS and
NHAMCS

• Many annual NCHS summary reports (for example,
  Health US) include mental health related data,
  such as trends in prescribing antidepressants
• Annual NAMCS and NHAMCS summary reports can
  include various mental health-related statistics
  (for example, statistics on visits to
  psychiatrists within tables by physician
  specialty)
• Some NCHS reports have focused specifically on
  visits to psychiatrists, alcohol/drug related
  visits, etc.

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User Considerations
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A few things to keep in mind

• NAMCS/NHAMCS sample visits, not patients
• No estimates of incidence or prevalence
• No state-level estimates
• We do not sample by setting or by non-physician
  providers with one exception
• Note that, from 2006, NAMCS includes a stratum of
  CHCs (community health centers), and
  non-physician providers are sampled within CHCs
• May capture different types of care for solo vs.
  group practice physicians
• May not have much data in a single year for less
  common conditions or events

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NAMCS vs. NHAMCS

• Consider what types of settings are best for a
  particular analysis
• Persons of color are more likely to visit OPDs
  and EDs than physician offices
• Persons in some age groups make
  disproportionately larger shares of visits to EDs
  than offices and OPDs

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Ways to Improve Reliability of Estimates

• Combine NAMCS, ED, and OPD data to produce
  ambulatory care visit estimates
• Combine multiple years of data
• Aggregate categories of interest into broader
  groups.

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Caveat on Counseling Services

• Diagnostic services are reflected accurately on
  medical records, but counseling services may not
  be
• NAMCS (and OPD) data may underestimate the amount
  of health habit counseling that occurs if it is
  not documented in the medical record
• These findings were published by in the following
  article Gilchrist VJ, Stange KC, Flocke SA,
  McCord G, Bourguet CC. A Comparison of the
  National Ambulatory Medical Care Survey (NAMCS)
  Measurement Approach With Direct Observation of
  Outpatient Visits. Medical Care 42(3), March
  2004, 276-280.

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How To Get the Data
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http//www.cdc.gov/nchs/namcs.htm
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Public Use Micro-data Files

• Downloadable files
• NAMCS, 1973-2006
• NHAMCS, 1992-2006
• CD-ROMs
• NAMCS, 1990-2005
• NHAMCS, 1992-2005

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Enhanced Public Use Files

• SAS input statements, label statements, and
  format statements (1993-2006)
• SPSS and Stata code for 2002-2006
• Masked sample design variables
• Allow use of SUDAAN, Stata, etc.
• Available for 1993-2006

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NCHS Research Data Center
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Advantages of the NCHSResearch Data Center

• Users gain access to information not available on
  public use files
• Patient ZIP code-linked income, education,
  poverty status, percent foreign born, percent not
  speaking English well, urban-rural classification
• Provider physician sex, age, and board
  certification, teaching hospital
• Geographic FIPS (Federal Information Processing
  Standard) state and county codes
• Special files and data supplements
• For a complete list of variables, contact the
  Ambulatory and Hospital Care Statistics Branch

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Research Data Center cont.

• Can merge with contextual variables (e.g., Area
  Resource File, National Health Interview Survey,
  National Hospital Discharge Survey Census)
• Health status level
• Health Maintenance Organization (HMO) penetration
• Physician and specialist supply
• Medicaid reimbursement
• Air quality
• Percent in poverty

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Research Data Center Procedures

• Submit a proposal
• May not use data to identify patients or
  providers or geographic location of providers
• May not remove data files
• Fees vary based on whether use is onsite or
  remote and whether project requires file
  construction by NCHS staff

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Research Data Center

• E-mail rdca_at_cdc.gov
• Website www.cdc.gov/nchs/rd/rdc.htm
• Call [phone]

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Additional Information

• Call the Ambulatory and Hospital Care Statistics
  Branch at [phone]
• Visit our website at www.cdc.gov/nhcs/namcs.htm
• Join the ACLIST. Its a moderated newsgroup for
  persons interested in NAMCS/NHAMCS. It currently
  consists of about 2,600 subscribers.