# Presentation: 656716

## Analyzing data on medications collected in the National Health Care Survey

***                      ******Catharine W. Burt , Ed.D. ***
***Chief, Ambulatory Care Statistics Branch***

***July 14, 2004 Data Users Conference***

## Slide 2

## Topics

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

## Slide 4

## 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

**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

## Slide 8

## Slide 9

## Slide 10

## Antibiotic prescribing rates at physician office visits for children 

- Rate per 1000 population

- Rate per 1000 visits

## NAMCS and NHAMCS background 

- NAMCS
- Fielded 1973-1981, 1985, 1989-present
- 3-stage sample
- PSUs –
-    physicians –
-    visits during 1 week
- NHAMCS
- Fielded annually since 1992
- 4-stage sample
- PSUs –
- 	hospitals –
- 	ED/OPD clinics –
-    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
- Nonfederally employed
- 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
- House calls, phone calls, emails, 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.

## Slide 18

## Items Collected

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

## Slide 20

## Using NAMCS/NHAMCS public use files for analyzing drug data

## Ambulatory Care Data Structure

## File Structure

- Flat ASCII files for each setting and year
- Use file layout to read the data
- Input and format code available for
- SAS
- STATA
- 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 |
| --- | --- | --- |
| Prozac
MED#=25674 | Fluoxetine
GEN#=80006 | Antidepressant
DRUGCL=0630 |
| Fluoxetine
MED#=91079 | Fluoxetine
Gen#=80006 | Antidepressant
DRUGCL=0630 |
| Fluoxetine HCL
MED#=91079
 | Fluoxetine
GEN#=80006 | Antidepressant
DRUGCL=0630 |

## Leading Rx at office visits % of all Rx mentions

- Lipitor  		       1.6%
- Albuterol		1.4
- 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

## http://www.cdc.gov/nchs/about/major/ahcd/ahcd1.htm

## Slide 30

##       Drug Characteristics Database Search 

**                    ****on Generic: ****Fluoxetine**
**                                                                                         ****1999**
**Drug Code  Drug Name    Generic Name                Mentions**
**   ****25674      PROZAC          FLUOXETINE**
**                                              ****HYDROCHLORIDE      9,257,694 **
**   ****91079    FLUOXETINE  FLUOXETINE**
**                                              ****HYDROCHLORIDE         49,293 **

##                       Drug Characteristics Database

**     ****Drug Code\Name:   25674 - ****PROZAC**** **
**Generic Code\Name:   80006 – 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:  9,257,694 **
**    ****1999 Mention Rate:  98.0 **

##                    Drug Characteristics Database 

**          ****Drug Code\Name:  91079 - ****FLUOXETINE **
**     ****Generic Code\Name:  80006 – 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:   49,293 **
**       ****1999 Mention Rate:   1.0 **

## Drug mention rates at physician office visits by patient’s age: 1985-2002

## Drug mention rates for NSAIDs, antidepressants, and antihistamines at physician office visits, 1995-2002

- 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, 1995-2002

- 65 years and over

- 45-64 years

- Number of drug mentions per 100 females.

## Rate of office visits for erectile dysfunction for men 25+: United States, 1985-2002

- Viagra introduced

- Figures are based on 2-year averages except 1985.  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 25-44 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%
- Hyperplasia of the prostate 11%
- Diabetes 8%

## Analyzing trends

- Be careful about trending diagnosis prior to 1980 because of  ICDA
-      (based on ICD-8)
- Even after 1980- be careful about changes in ICD-9-CM
- Number of medications varies over years		**1980-81 – 8 medications**
**	****	****	****1985, 1989-94 – 5 medications**
**	****	****	****1995-2002 – 6 medications**
**	****	****	****2003-2006 – 8 medications**
- Number of therapeutic class codes vary
**1980-2001 – 1 class**
**2002-2006 – up to 3 classes**

## Information available on the Internet

- NCHS website is www.cdc.gov/nchs
- National Health Care Survey website
- Ambulatory Health Care Data (AHCD)
- National Hospital Discharge and Ambulatory Surgery Data (NHDAS-data)
- National Nursing Home Survey (NNHS)
- National Home and Hospice Care Survey (NHHCS)
- Join our LISTSERVs

**Notes:**
Added the acromyns for NNHS and NHHCS – replace slide # 53