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


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


National Hospital Ambulatory Medical Care Survey (NHAMCS) ... psychiatry, neurology, ophthalmology, otolaryngology, and an 'other' category ... – PowerPoint PPT presentation

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

Mental Health Data from the NAMCS and
NHAMCSSusan M. Schappert, M.A.Ambulatory and
Hospital Care Statistics BranchDivision of
Health Care Statistics
Topics To Be Covered
  • Survey Overview
  • Data Collected
  • Published Mental Health Research Using Data from
  • User Considerations
  • How to Get the Data

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

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

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

NAMCS Sample Design
  • Three stage design
  • 112 primary sampling units (counties/groups of
  • 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

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

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

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
  • 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
  • 80 psychiatrists reported on nearly 1,400 visits
    (4.7 of total)

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

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

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

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
  • Located in 50 states and D.C.

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

Data Collected in the NAMCS and NHAMCS
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
  • 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.

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

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

Mental Health Items Collected inNAMCS and
  • 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
  • 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,
  • Mental health counseling (1995-2000)
  • Mental health/stress management counseling
  • Other mental health counseling (2005-06)

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
  • 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)

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
  • Multiple procedure codes for NAMCS and OPD

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

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
  • Respondents are asked to report trade names or
    generic names only (not dosage, administration,
    or regimen). Cannot link drugs with diagnosis.

  • 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

Published Mental Health Research Using Data from
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
  • 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,
  • pharmacotherapy (antidepressants, antipsychotics,
    hypnotics, stimulants, psychotropics in general)
  • mental health care by physicians other than
  • racial/ethnic/gender disparities in mental health
  • other topics such as self-harm (ED visits),
    insurance issues, substance abuse

Additional Mental Health Data from NAMCS and
  • 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
  • Some NCHS reports have focused specifically on
    visits to psychiatrists, alcohol/drug related
    visits, etc.

User Considerations
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

  • 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

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

Caveat on Counseling Services
  • Diagnostic services are reflected accurately on
    medical records, but counseling services may not
  • 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.

How To Get the Data
Public Use Micro-data Files
  • Downloadable files
  • NAMCS, 1973-2006
  • NHAMCS, 1992-2006
  • CD-ROMs
  • NAMCS, 1990-2005
  • NHAMCS, 1992-2005

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

NCHS Research Data Center
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

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

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

Research Data Center
  • E-mail
  • Website
  • Call (301) 458-4277

Additional Information
  • Call the Ambulatory and Hospital Care Statistics
    Branch at (301) 458-4600
  • Visit our website at
  • Join the ACLIST. Its a moderated newsgroup for
    persons interested in NAMCS/NHAMCS. It currently
    consists of about 2,600 subscribers.