Analyzing data on medications collected in the National Health Care Survey Centers for Disease Control and Prevention National Center for Health Statistics Catharine W. Burt, Ed.D. Chief, Ambulatory Care Statistics Branch June 6, 2004 AcademyHealth Conference

Topics  Overview of the NHCS  Background of the ambulatory care surveys  Using public use files for drug analysis  Examples of drug analyses

Ambulatory care Long-term care National Health Care Survey Basic Components Hospital & surgical care Health Provider Inventory

National Health Care Survey (Year began collecting drug data)  National Ambulatory Medical Care Survey (1980)  National Hospital Ambulatory Medical Care Survey (1992)  National Hospital Discharge Survey (in research)  National Survey of Ambulatory Surgery (1994-6)  National Nursing Home Survey (2004)  National Home and Hospice Care Survey

Increasing drug mentions at ambulatory care visits

NHCS Common Methodology   National probability sample surveys   Complex sample designs   Common definitions, data items, sampling frames   Medical diagnoses coded to ICD-9-CM   Data collected by Census Bureau   High response rates   Data processed by private contractor

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

NAMCS and NHAMCS background  NAMCS Fielded , 1985, 1989-present Fielded , 1985, 1989-present 3-stage sample 3-stage sample PSUs –PSUs – physicians – physicians – visits during 1 week visits during 1 week  NHAMCS Fielded annually since 1992 Fielded annually since stage sample 4-stage sample PSUs –PSUs – hospitals – ED/OPD clinics – visits during 4 weeks visits during 4 weeks SEs rates percents drugs providers visits sample records

Scope of the NAMCS  Physicians must be: Primarily engaged in office-based, patient care Primarily engaged in office-based, patient care Nonfederally employed Nonfederally employed Not in anesthesiology, radiology, or pathology Not in anesthesiology, radiology, or pathology

In-Scope Visits for NAMCS  Basic unit of sampling is the physician- patient visit  Visit must occur in a physician’s office  Visits must be for medical purposes  Out-of-scope contacts include: Visits for administrative purposes Visits for administrative purposes House calls, phone calls, s, visits in hospital setting unless physician has private office there House calls, phone calls, s, visits in hospital setting unless physician has private office there

In-Scope NAMCS Locations  Freestanding private solo or group practice  Freestanding clinic/urgicenter  Neighborhood medical and mental health centers  Privately operated clinics  Non-Federal government clinic  Health maintenance organization  Federally qualified health center  Faculty practice plan

Out-of-Scope NAMCS Locations  Hospital ED’s and OPD’s  Ambulatory surgicenter  Institutional setting (schools, prisons)  Industrial outpatient facility  Federally operated clinic  Laser vision surgery

Scope of the NHAMCS  Basic unit of sampling is patient visit  Emergency and outpatient departments of non-federal, general and short-stay hospitals  Not Federal, military, or Veterans Administration facilities  Located in 50 states and D.C.

Items Collected  Patient characteristics Age, sex, race, ethnicity Age, sex, race, ethnicity  Visit characteristics Source of payment, continuity of care, reason for visit, diagnosis, treatment, medications ordered or provided Source of payment, continuity of care, reason for visit, diagnosis, treatment, medications ordered or provided  Provider characteristics Physician specialty, hospital ownership Physician specialty, hospital ownership  Drug characteristics Therapeutic class, composition, control status, ingredients, Rx or OTC Therapeutic class, composition, control status, ingredients, Rx or OTC

Using NAMCS/NHAMCS public use files for analyzing drug data

Ambulatory Care Data Structure Provider provider info practice info geographic info Visit patient & visit info treatment & outcome info medications Medcode 1 Class 1 …Class 3 …Medcode 6 Ingredient 1..ingredient 5 Visit

File Structure  Flat ASCII files for each setting and year  Use file layout to read the data  Input and format code available for SAS SAS STATA STATA SPSS SPSS  Can use SETS (but no sampling variance estimates)

Visit File Layout

Sample Weight  Each NAMCS, OPD and ED record contains a single weight, which we call Patient Visit Weight  This weight is used for both visits and drug mentions  Weight must be applied or estimates of totals, percents and effects will be incorrect.

Drug coding Drug name Generic name Therapeutic class ProzacMED#=25674FluoxetineGEN#=80006AntidepressantDRUGCL=0630 FluoxetineMED#=91079FluoxetineGen#=80006AntidepressantDRUGCL=0630 Fluoxetine HCL MED#=91079FluoxetineGEN#=80006AntidepressantDRUGCL=0630

Leading Rx at office visits % of all Rx mentions  Lipitor 1.6%  Albuterol1.4  Amoxicillin 1.3  Synthroid 1.3  Lasix 1.2  Celebrex 1.2  Vioxx 1.1 Source: 2002 NAMCS

Top OTC mentions at office visits % of all OTC mentions  Aspirin 16.7%  Tylenol 11.6  Advil 4.1  Prenatal vitamins 3.4  Benadryl 3.2 Source: 2002 NAMCS

Drug Characteristics Database Search on Generic: Fluoxetine 1999 Drug Code Drug Name Generic Name Mentions PROZAC FLUOXETINE HYDROCHLORIDE 9,257, FLUOXETINE FLUOXETINE HYDROCHLORIDE 49,293

Drug Characteristics Database Drug Code\Name: PROZAC Generic Code\Name: – FLUOXETINE HYDROCHLORIDE Date Added: No Date Prescription Status: 1 - Prescription Drug Composition Status: 1 - Single Entity Drug DEA Status: 6 - No Control Therapeutic Class: 0630 Antidepressants 1999 Mentions: 9,257, Mention Rate: 98.0

Drug Characteristics Database Drug Code\Name: FLUOXETINE Generic Code\Name: – FLUOXETINE HYDROCHLORIDE Date Added: No Date Prescription Status: 1 - Prescription Drug Composition Status: 1 - Single Entity Drug DEA Status: 6 - No Control Therapeutic Class: 0630 Antidepressants 1999 Mentions: 49, Mention Rate: 1.0

Drug mention rates at physician office visits by patient’s age:

Drug mention rates for NSAIDs, antidepressants, and antihistamines at physician office visits, Number of drug mentions per 100 visits NSAIDs are nonsteroidal anti-inflammatory drugs. Trends shown are significant (p<0.05). NSAIDs Antidepressants Antihistamines

Estrogen/progestin mention rates for women at physician office visits by patient age, years and over years Number of drug mentions per 100 females.

Rate of office visits for erectile dysfunction for men 25+: United States, Viagra introduced Figures are based on 2-year averages except SOURCE: NAMCS

Example of NAMCS analysis for Viagra  Prescribed at.4% of office visits by males; 15% of erectile dysfunction (ED) visits  12% scripts written for men aged and 9% for 75+  Rate of scripts increases for patients who have seen their physician between 1 and 5 times in past year. Rarely prescribed at an initial visit.  Only 19% of scripts written are at ED visits  Leading diagnoses when ED not listed– Essential hypertension 19% Essential hypertension 19% Hyperplasia of the prostate 11% Hyperplasia of the prostate 11% Diabetes 8% Diabetes 8%

Analyzing trends  Be careful about trending diagnosis prior to 1980 because of ICDA (based on ICD-8) (based on ICD-8)  Even after be careful about changes in ICD-9-CM  Number of medications varies over years – 8 medications 1985, – 5 medications – 6 medications – 8 medications  Number of therapeutic class codes vary – 1 class – up to 3 classes

Information available on the Internet  NCHS website is  National Health Care Survey website Ambulatory Health Care Data (AHCD) Ambulatory Health Care Data (AHCD) National Hospital Discharge and Ambulatory Surgery Data (NHDAS-data) National Hospital Discharge and Ambulatory Surgery Data (NHDAS-data) National Nursing Home Survey (NNHS) National Nursing Home Survey (NNHS) National Home and Hospice Care Survey (NHHCS) National Home and Hospice Care Survey (NHHCS)  Join our LISTSERVs