• Component Description
• Eligible Sample
• Interview Setting and Mode of Administration
• Quality Assurance & Quality Control
• Data Processing and Editing
• Analytic Notes
• References
• Codebook
  • SEQN - Respondent sequence number
  • RXQ510 - Dr told to take daily low-dose aspirin?
  • RXQ515 - Followed advice, took low-dose aspirin?
  • RXQ520 - Taking low-dose aspirin on your own?

National Health and Nutrition Examination Survey

2017-March 2020 Data Documentation, Codebook, and Frequencies

Preventive Aspirin Use (P_RXQASA)

Data File: P_RXQASA.xpt

First Published: June 2021

Last Revised: NA

Component Description

The NHANES program suspended field operations in March 2020 due to the coronavirus disease 2019 (COVID-19) pandemic. As a result, data collection for the NHANES 2019-2020 cycle was not completed and the collected data are not nationally representative. Therefore, data collected from 2019 to March 2020 were combined with data from the NHANES 2017-2018 cycle to form a nationally representative sample of NHANES 2017-March 2020 pre-pandemic data. These data are available to the public. Please refer to the Analytic Notes section for more details on the use of the data.

The NHANES 2017-Mar 2020 Preventive Aspirin Use questionnaire data (P_RXQASA) provides self-reported information on low-dose aspirin taken to prevent heart attacks, strokes, and cancer. Cardiovascular disease (CVD) remains the leading cause of death in the United States. Low-dose aspirin might be considered for primary prevention of CVD among select adults aged 40-70 years who are at higher CVD risk but not at increased bleeding risk (Arnett DK et al, 2019). Increasing aspirin use among individuals who are at high risk for CVD is one of the key Public Health objectives in the U.S. (Frieden & Berwick, 2011).

P_RXQASA data collection topics include:

• Whether a doctor recommended low dose aspirin for preventive use.
• Adherence to this medical advice; and whether aspirin was stopped due to side effects.
• Whether the low-dose aspirin was taken on one’s own initiative.

The P_RXQASA data collection format was designed to provide both current and lifetime prevalence estimates of preventive aspirin use: overall use; doctor recommended use; and self-initiated use. When combined with other NHANES data, the prevalence of low-dose aspirin use for both primary and secondary prevention can be estimated, as well as the prevalence of aspirin use in key population subgroups: those with coronary artery disease, angina, heart attack, stroke, and diabetes. Also, preventive aspirin use prevalence can be monitored across the major demographic subgroups, such as age, gender, and race and Hispanic origin.

Eligible Sample

All participants aged 40 year and older in the NHANES 2017-March 2020 pre-pandemic sample are included in this dataset.

Survey participants between 20 and 39 years of age who reported having a history of coronary heart disease, heart attack, angina, and/or stroke were also eligible. Data obtained from this small subgroup are available through the NCHS Research Data Center only.

Interview Setting and Mode of Administration

These questions were asked, in the home, by trained interviewers using the Computer-Assisted Personal Interview (CAPI) system. They were administrated as part of Dietary Supplements and Prescription Medication section of the Sample Person Questionnaire, which collects information on dietary supplements, nonprescription antacids, and prescription medication.

The NHANES 2017-2018 and 2019-2020 preventive aspirin use questionnaires are available on the NHANES website.

Quality Assurance & Quality Control

The CAPI system is programmed with built-in consistency checks to reduce data entry errors. CAPI also uses online help screens to assist interviewers in defining key terms used in the questionnaire.

Data Processing and Editing

Frequency counts were checked, “skip” patterns were verified, and the reasonableness of question responses was reviewed. Edits were made to ensure the completeness, consistency, and analytic usefulness of the data. 

Analytic Notes

The COVID-19 pandemic required suspension of NHANES 2019-2020 field operations in March 2020 after data was collected in 18 of the 30 survey locations in the 2019-2020 sample. Because the collected data from 18 locations were not nationally representative, these data were combined with data from the previous cycle (2017-2018) to create a 2017-March 2020 pre-pandemic data file. The resulting sample weights in the demographic file should be used to calculate estimates from the combined cycles. The sample weights are not appropriate for independent analyses of the 2019-2020 data and will not yield nationally representative results for either the 2017-2018 data alone or the 2019-March 2020 data alone. Please refer to the NHANES website for additional information for the NHANES 2017-March 2020 pre-pandemic data, and for the previous 2017-2018 public use data file with specific weights for that 2-year cycle.

Same as the previous publicly release data files, P_RXQASA data is formatted as person-level data, where each participant has only one record. Questions related to the frequency and dosage of aspirin use (variables RXQ525G, RXQ525Q, RXQ525U, RXD530) were not collected in 2019-March 2020 so they are not included in the P_RXQASA data file. The low-dose aspirin reported in this data is usually available over-the-counter without prescription. However, some state laws might require prescriptions for such over-the-counter medications. Also, sometimes physicians might write prescriptions for preventive aspirin. The P_RXQASA data, for the most part, represents the non-prescription over-the-counter aspirin use; however, the few instances where prescription aspirin was used for preventive purposes are also included in this data file.

The analysis of NHANES aspirin use questionnaire data must be conducted using the appropriate survey design variables, sample weights, and the basic demographic variables in the 2017-Mar2020 demographic data file. Interview weights should only be used if questionnaire data are analyzed by themselves. However, if P_RXQASA data are merged with the MEC examination data or laboratory data, the MEC examination weights should be used for analyses. If P_RXQASA data are merged with laboratory sub-sample data, sub-sample weights should be used for analyses.

Please refer to the NHANES Analytic Guidelines and the on-line NHANES Tutorial for further details on the use of sample weights and other analytic issues.

References

• Arnett DK, Blumenthal RS, Albert MA et. al. 2019 ACC/AHA Guidelines on the Primary Prevention of Cardiovascular Disease: Executive Summary. A Report of the American College of Cardiovascular/American Heart Association Task Force on Clinical Practice Guidelines. Circulation. 2019; 140: e563-e594.
• Frieden TR, Berwick DM. The "Million Hearts" initiative--preventing heart attacks and strokes. N Engl J Med. 2011 Sep 29;365(13):e27.

Codebook and Frequencies