Ambulatory Health Care Data

Ambulatory Care Monthly News

June 2020

STATS OF THE MONTH

In recognition of Alzheimer’s and Brain Awareness Month (June 1-30), we present estimates for visits to emergency departments (ED) made by patients with Alzheimer’s disease or dementia documented in their medical records, from the 2017 National Hospital Ambulatory Medical Care Survey (NHAMCS).

  • In 2017, approximately 1.8 million ED visits were made by patients with Alzheimer’s disease or dementia documented in their medical record, accounting for 1.7% of all ED visits made by adults. More visits were made by women with Alzheimer’s disease or dementia documented in the medical record (1.1%) than men (0.6%).  (Estimates from the Public Use File).

DATA TIP OF THE MONTH

Did you know . . .

NHAMCS public use files are provided in ASCII text format that allow the data to be used by many software products. NCHS provides sample SAS statements, SPSS and Stata code for use with NHAMCS data files from 1992 forward. The survey undergoes periodic redesign, which can make the process of combining multiple years of data challenging. NCHS staff make every effort to point out important changes in the annual public use file documentation. Staff members are also available to answer technical questions 301-458-4600.

NEW PRODUCTS THIS MONTH

  • Ashman JJ, Schappert SM, Santo L. Emergency department visits among adults aged 60 and over: United States, 2014–2017. NCHS Data Brief, no 367. Hyattsville, MD: National Center for Health Statistics. 2020. This data brief shows that in 2014–2017, the emergency department (ED) visit rate for persons aged 60 and over was 43 visits per 100 persons aged 60 and over and increased with age. About 7% of ED visits among patients aged 60 and over were made by nursing home residents, 30% of patients arrived by ambulance and unintentional falls accounted for 13% of ED visits made by patients aged 60 and over. Nearly one-quarter of ED visits among patients aged 60 and over resulted in a hospital admission, and this percentage increased with age. 

 

May 2020

STATS OF THE MONTH
In recognition of National Women’s Health Week (May 10-16), we present estimates for visits to emergency departments (ED) made by women from the 2017 National Hospital Ambulatory Medical Care Survey (NHAMCS).

  • In 2017, approximately 61 million visits were made to the ED by women aged 18 and over, accounting for 58.1% of all adult visits to the ED. Abdominal pain, cramps and spasms was the most common reason for visit among women 18 and over (8.7%), followed by chest pain (5.4%), headache (3.5%), shortness of breath (3.3%), and cough (2.8%). (Estimates from the Public Use File).

DATA TIP OF THE MONTH

Did you know . . .

Missing values are imputed every year for some items. Starting with 2010 data, the imputation of patient race and ethnicity was performed using a model-based single, sequential regression method. The model used to impute race and ethnicity in 2017 NHAMCS included the following variables: Census variables for ZIP code level race and ethnicity population estimates and an indicator for whether it was patient or hospital ZIP (used when patient ZIP was not available); patient age, sex, race, and ethnicity; triage level; log of ED wait time; primary expected source of payment derived from a hierarchical recode of the expected source of payment question; grouped 3-digit ICD-10-CM codes for primary diagnosis; year of visit; type of ESA area; provider’s MSA status; and ED weighting and volume variables. The list of items with a nonresponse rate greater than 5% and the list of the imputed items can be found here starting on page 13 pdf icon[PDF – 14 KB].

NEW PRODUCTS THIS MONTH

 

April 2020

STATS OF THE MONTH
In recognition of Alcohol Awareness Month (April 1-30), we present estimates for visits to emergency departments (ED) made by patients with alcohol misuse, abuse, or dependence, documented in the medical record from the 2017 National Hospital Ambulatory Medical Care Survey (NHAMCS).

  • In 2017, patients with alcohol misuse, abuse, or dependence, documented in the medical record accounted for 3.1% of all visits to the ED. Visits made by patients with alcohol misuse, abuse, or dependence in the medical record varied by sex, with a higher percentage of visits being made by males (4.7%) than females (1.8%). (Estimates from Table 13 pdf icon[PDF – 864 KB] and Public Use File)

DATA TIP OF THE MONTH

Did you know . . .

For NHAMCS 2017, anomalies between 2017 and 2016 data were assessed. To accomplish this, more than 20 tables of 2017 estimates were compared with the same tables of 2016 estimates. The variables that were compared included most of those published in the annual survey web tables available here. Significant changes between the two years were noted and investigated. More information about the changes can be found in the 2017 NHAMCS Public use file documentation.

 

March 2020

STATS OF THE MONTH
In recognition of National Kidney Month (March 1-31), we present estimates for visits to emergency department (ED) for chronic kidney disease (CKD) from the 2017 National Hospital Ambulatory Medical Care Survey (NHAMCS).

  • In 2017, patients with CKD documented in the medical record accounted for 2.9% of all visits to the ED and for 3.7% of all visits to the ED visits made by adults aged 18 and over. Visits made by adults patients with CKD in the medical record increased by age, more visits were made by adult aged 65 and over (10%) than adult aged 45-64 (4.4%) and adults aged 18-44 (0.6%). (Estimates from Table 13 pdf icon[PDF- 863 KB] and Public Use File)

DATA TIP OF THE MONTH

Did you know . . .

A new template for producing Methods sections of journal articles using NHAMCS data covering data years 1992-2016 is available here pdf icon[PDF – 28 KB]. The document also provides a useful checklist for NHAMCS article submission.

NEW PRODUCTS THIS MONTH

  • Santo L, Ward BW, Rui P, Ashman JJ. Antineoplastic drugs prescription during visits by adult cancer patients with comorbidities: findings from the 2010-2016 National Ambulatory Medical Care Surveyexternal icon. Cancer Causes Control. 2020 Feb 21. doi: 10.1007/s10552-020-01281-5. This manuscript uses 2010-2016 National Ambulatory Medical Care Survey to describe the frequency of comorbidities at visits by patients with breast, prostate, colorectal, and lung cancer and the frequency of a prescription for antineoplastic drugs being included in the treatment received at visits by patients with cancer and concomitant comorbidities. The authors show that among US visits by adult patients with breast, prostate, colorectal, or lung cancer, 56.3% were by patients with ≥ 1 comorbidity. Hypertension was the most frequently observed comorbidity (37.7%), followed by hyperlipidemia (19.0%) and diabetes (12.3%). Antineoplastic drugs were prescribed in 33.5% of the visits.

 

February 2020

STATS OF THE MONTH

In recognition of American Heart Month (February 1-29), we present estimates for visits to emergency department (ED) for coronary artery disease, ischemic heart disease, or history of myocardial infarction (MI) from the 2017 National Hospital Ambulatory Medical Care Survey (NHAMCS).

  • In 2017, patients with coronary artery disease, ischemic heart disease, or history of MI documented in the medical record accounted for 6.1% of all  visits to the ED and for 22.3% of the ED visits made by adults aged 65 and over.  More visits were made by male aged 65 and over (28.1%) than female aged 65 and over (18.2%) with coronary artery disease, ischemic heart disease, or history of MI documented in the medical record.  (Estimates from Table 13 pdf icon and Public Use File)
  • In 2017, chest pain and related symptoms was the primary reason for visit in 5.7% of all visits to the emergency department (ED) made by adults aged 18 and over. Visits with chest pain and related symptoms as primary reason for visit were higher among patients aged 55 and over (6.9%) than among patients aged 18-54 (5.1%). (Estimates from the Public Use File)

DATA TIP OF THE MONTH

Did you know . . .

To  calculate department-level estimates an emergency department weight (EDWT) can be used. When running an analysis of facility-level characteristics using EDWT, it is recommended to select only those records where EDWT is greater than 0. This will result in correct sample counts of variables, which is useful for assessing reliability. Estimates at the ED level generated using EDWT reflect only the characteristics of facilities which participated in the survey.

NEW PRODUCTS THIS MONTH

  • 2017 NHAMCS EMERGENCY DEPARTMENT SUMMARY WEB TABLES pdf icon – The Ambulatory and Hospital Care Statistics Branch is pleased to release the most current nationally representative data on ambulatory care visits to hospital emergency departments (ED) in the United States. Estimates are presented on selected hospital, patient, and visit characteristics using data collected in the 2017 NHAMCS.
  • QuickStats: Percentage of Emergency Department Visits for Pain at Which Opioids Were Given or Prescribed, by Geographic Region of the Hospital — United States, 2005–2017. MMWR Morb Mortal Wkly Rep 2020;69:53. This quickstas shows that the percentage of ED visits for pain at which an opioid was given or prescribed increased from 37.4% in 2005 to 43.1% in 2010 and then decreased to 30.9% in 2017. A similar pattern was observed in all four regions. In 2017, the percentage was 21.1% in the Northeast, compared with 32.0% in the Midwest, 32.0% in the South, and 34.7% in the West.
  • QuickStats: Percentage of Emergency Department Visits for Acute Viral Upper Respiratory Tract Infection at Which an Antimicrobial Was Given or Prescribed, by Age — United States, 2010–2017. MMWR Morb Mortal Wkly Rep 2020;69:174. This quickstats shows that the percentage of ED visits for acute viral upper respiratory tract infection that had an antimicrobial given or prescribed, decreased from 23.4% in 2010-2013 to 17.6% in 2014-2017. A decline was seen for ED visits by children, decreasing from 17.9% to 10.1%, but not for ED visits by adults.

 

January 2020

 YEAR IN REVIEW

Publications from NAMCS in 2019

NCHS reports and data briefs

Web tables

  • 2013 NAMCS Community Health Center (CHC) Web Tables pdf icon[PDF – 669 KB]. Rui P, Kang K, Yacisin K, Okeyode T. National Ambulatory Medical Care Survey – Community Health Centers: 2013 State and National Summary Tables. Nationally representative data on ambulatory care visits to community health centers in the United States are presented on selected provider, patient, and visit characteristics using data collected in the 2014 NAMCS Community Health Center component.
  • 2016 NAMCS SUMMARY WEB TABLES pdf icon[PDF – 906 KB] – The most current nationally representative data on ambulatory care visits to physician offices in the United States are presented on selected physician, patient, and visit characteristics using data collected in the 2016 NAMCS.
  • 2014 NAMCS Community Health Center Summary Tables pdf icon[PDF – 584 KB]: The most current nationally representative data on ambulatory care visits to community health centers in the United States are presented on selected provider, patient, and visit characteristics using data collected in the 2014 NAMCS Community Health Center component.

Manuscripts

  • Akinbami LJ, Salo PM, Cloutier MM, Wilkerson JC, Elward KS, Mazurek JM, Williams S, Zeldin DC. Primary care clinician adherence with asthma guidelines: the National Asthma Survey of Physicians. J Asthma. 2019 Mar 1:1-13external icon. This article examines adherence to asthma guidelines by using the 2012 National Asthma Survey of Physicians (NAS): a one-time provider questionnaire supplement to National Ambulatory Medical Care Survey (NAMCS). The authors found that pediatricians were more likely to report high adherence than other clinicians and adherence was higher for history-taking recommendations and lower for recommendations involving patient education, equipment and expertise.
  • Santo L, Rui P, Hales CM, Arem H, Ogden CL. Am J Prev Med. 2019 Nov;57(5):716-717. Trends in Preventive Visits Among U.S. Youth Where Weight and Height Were Recorded: 2005-2016external icon. This research letter provides trends in preventive visits from 2005 through 2016 in which weight and height were recoded among children and adolescents. The authors found that overall, the percentage of preventive visits in which weight and height were recorded increased from 87.6% in 2005 to 95.6% in 2016. Similar trends were found among children and adolescents.

Publications from NHAMCS in 2019

NCHS reports, data briefs and quickstats

Web tables

  • 2016 NHAMCS EMERGENCY DEPARTMENT SUMMARY WEB TABLES pdf icon[PDF- 978 KB] – The Ambulatory and Hospital Care Statistics Branch is pleased to release the most current nationally representative data on ambulatory care visits to hospital emergency departments (ED) in the United States. Estimates are presented on selected hospital, patient, and visit characteristics using data collected in the 2016 NHAMCS.

NEW PRODUCTS THIS MONTH

  • Trends in opioids prescribed at discharge from emergency departments among adults: United States, 2006–2017 pdf icon[PDF – 436 KB]. Rui P, Santo L, Ashman JJ. National Health Statistics Reports; no 135. Hyattsville, MD: National Center for Health Statistics. 2020. This report describes trends in ED visits made by adult patients at which opioids were prescribed at discharge from 2006-2007 to 2016-2017. The authors found that the percentage of ED visits by adults with opioids prescribed at discharge increased from 2006–2007 (19.0%) through 2010–2011 (21.5%) and then decreased from 2010–2011 through 2016–2017 (14.6%). The top five diagnoses associated with an opioid prescribed at discharge were dental pain, urolithiasis, fracture injuries, back pain, and extremity pain.
  • Physician office visits at which benzodiazepines were prescribed: Findings from 2014–2016 National Ambulatory Medical Care Survey pdf icon[PDF – 376]. Santo L, Rui P, Ashman JJ. National Health Statistics Reports; no 137. Hyattsville, MD: National Center for Health Statistics. 2020. This report describes visits to office-based physicians made by adult patients at which benzodiazepines were prescribed, including visits were opioids were coprescribed. The authors found that during 2014–2016, the rate of visits at which benzodiazepines were prescribed was 27 annual visits per 100 adults and one-third of these visits involved an overlapping opioid prescription. Mental disorders were the most frequent primary diagnosis category for visits at which benzodiazepines were prescribed, whereas diseases of the musculoskeletal system and connective tissue was the most frequent primary diagnosis category for visits at which benzodiazepines were coprescribed with opioids.

DATA TELL STORIES
Tell Us Yours! How have you used information from the National Ambulatory Medical Care Survey or the National Hospital Ambulatory Medical Care Survey? Email us a brief description at ambcare@cdc.gov. In the subject field of your email, write “My NAMCS/NHAMCS data use example”. Your examples will help us showcase the value of NAMCS and NHAMCS.

 

December 2019

STATS OF THE MONTH

In recognition of World AIDS Day (December 1), we present estimates for HIV/AIDS from the 2014-2016 National Ambulatory Medical Care Survey (NAMCS).

  • In 2014-2016, there were approximately 2.47 million visits per year to office-based physicians made by adults with HIV or AIDS in their medical record, accounting for 0.3% of all office-based physician visits made by adults. Visits made by men with HIV or AIDS in the medical record accounted for 0.6% of the visits made by men aged 18 and over, whereas visits made by women accounted for 0.1% of the visits made by women aged 18 and over. (Estimates from the Public Use File)

In recognition of National Influenza Vaccination Week (December 1-7), we present estimates for visits to emergency departments (ED) at which an influenza test was provided from the 2017 National Hospital Ambulatory Medical Care Survey (NHAMCS).

  • In 2017, an influenza test was provided at 4.1% of all ED visits. Children and adolescents younger than 18 were tested for influenza more frequently than adults. Children and adolescents were tested at 7.5% of the ED visits made by children and adolescents whereas adults aged 18-65 and 65 and over were tested for influenza at 3.1% and 2.7% of the visits made by adults. (Estimates from the Public Use File)

DATA TIP OF THE MONTH

Did you know…

The National Center for Health Statistics considers an estimated number of visits or a visit rate to be reliable if it has a relative standard error of 30 percent or less, and it is based on at least 30 sample records. NCHS recently released new guidelines for determining the reliability of proportions. These standards are based on a minimum denominator sample size and on the absolute and relative widths of a confidence interval calculated using the Clopper-Pearson method. The guidelines can be found here pdf icon[PDF – 144 MB].

NEW PRODUCTS THIS MONTH

 

November 2019

STATS OF THE MONTH

In recognition of COPD awareness month (November 1-30), we present estimates for chronic obstructive pulmonary disease (COPD) visits from the 2016 National Ambulatory Medical Care Survey (NAMCS).

  • In 2016, patients with COPD documented in the medical record accounted for 3.6% of the visits made to office-based physicians. Visits by patients with COPD increased with age. Only 0.5% of visits made by patients aged 45 and under had COPD in the medical record whereas 4.3% of visits made by patients aged 45-64, 7.0% of visits made by patients aged 65-74 and 8.8% of visits made by patients aged 75 and over had COPD in the medical record. (Estimates from Table 18 pdf icon[PDF – 907 KB])

In recognition of American Diabetes Month (November 1-30), we present estimates for visits to emergency departments (ED) for diabetes from the 2016 National Hospital Ambulatory Medical Care Survey (NHAMCS).

    • In 2016, adults with diabetes* documented in the medical record accounted for 14.5% of all ED visits made by adults. Visits by adults with diabetes increased with age; 5.3% of visits made by adults aged 18-44 had diabetes in the medical record whereas 20.6% and 27.6% of visits made by adults aged 45-64 and 65 and over, respectively, had diabetes in the medical record (Estimates from the Public Use File)

*includes diabetes mellitus type 1, type 2 and unspecified.

DATA TIP OF THE MONTH

Did you know…

Multiple years of data can be combined to improve reliability of estimates, which is necessary for rare estimates. When combining multiple years, it is easier for the reader to understand an average annual estimate rather than the total number of visits that occurred during the study period. For example, it is preferable to report that from 2012-2016, the average annual number of office-based physician visits for condition X was 5 million rather than from 2012-2016, there were 25 million visits for condition X.

NEW PRODUCTS THIS MONTH

 

OCTOBER 2019

STATS OF THE MONTH

In recognition of National Primary Care week (October 1-5), we present estimates for primary care visits from the 2016 National Ambulatory Medical Care Survey (NAMCS).

  • In 2016, approximately 374 million visits were made to primary care providers, accounting for 42.3% of all visits made to office-based physicians. Approximately 95% of the visits to primary care providers were made by established patients and 5% by new patients. (Estimates from Table 7 pdf icon[PDF – 906 KB])

In recognition of Respiratory Care week (October 20-26), we present estimates for visits to emergency departments (ED) related to diseases of the respiratory system from the 2016 National Hospital Ambulatory Medical Care Survey (NHAMCS).

  • In 2016, diseases of the respiratory system were the primary diagnosis at approximately 15 million visits to the ED, accounting for 10.2% of all ED visits. (Estimates from Table 11 pdf icon[PDF – 978 KB])
  • In 2016, patients with asthma documented in the medical record accounted for 10.1% of all ED visits, whereas patients with chronic obstructive pulmonary disease accounted for 5.6% of all ED visits. (Estimates from Table 13 pdf icon[PDF – 978 KB])

DATA TIP OF THE MONTH

Did you know…

The Research Data Center contains records for NAMCS physicians who are not included on the public use files for various reasons (did not see patients during reporting week or did not submit visit forms). Including these physicians in one’s analysis along with those who saw patients can provide national estimates of all office-based physicians.

NEW PRODUCTS THIS MONTH

 

September 2019

STATS OF THE MONTH

In recognition of Prostate Cancer Awareness Month (September 1-30), we present estimates for prostate cancer visits from the 2016 National Ambulatory Medical Care Survey (NAMCS).

  • In 2016, malignant neoplasm of prostate was the primary diagnosis at approximately 2.5 million visits made to office-based physicians accounting for 0.3% of all office-based physicians visits and 10.5% of all visits with a primary diagnosis of a malignant neoplasm. (Estimates from Table 15 pdf icon[PDF – 906 KB] and the Public Use File)

In recognition of Pain Awareness Month (September 1-30), we present estimates for visits to emergency departments (ED) related to stomach and abdominal pain, cramps, and spasms from the 2016 National Hospital Ambulatory Medical Care Survey (NHAMCS).

  • In 2016, stomach and abdominal pain, cramps, and spasms was the top principal reason for visiting an ED, accounting for 8.6% of all ED visits. Abdominal pain visits for females were higher than visits for males for both younger and older age groups (females aged 15-64 (7.0%) and males aged 15-64 (3.3%) and females aged 65 and over (4.7%) and males aged 65 and over (2.9%)). (Estimates from Table 10 pdf icon[PDF – 978 KB])

DATA TIP OF THE MONTH

Did you know…

A problem was found with the checkbox for CHF (Congestive Heart Failure) in the item: “Regardless of the diagnoses written above, does the patient now have:”. This checkbox is typically edited to ensure that any diagnoses of CHF reported in the survey items DIAG1-DIAG5 (Diagnosis #1 – Diagnosis #5) are also reflected in the CHF check box. It was recently discovered that the ICD-10-CM codes I50.1-I50.9 (Heart Failure) were not included in the edit. In all, 28 2016 NAMCS records and 45 2016 NHAMCS ED records with a diagnosis of Heart Failure reported in DIAG1-DIAG5 should have had the CHF checkbox checked but did not. More information is available here.

 

August 2019

STATS OF THE MONTH

In recognition of National Immunization Awareness Month we present estimates for immunization from the 2016 National Ambulatory Medical Care Survey (NAMCS).

  • In 2016, an immunization was provided at 32.2% of the preventive care visits made by patients aged 18 and younger. The percentage of preventive care visits in which an immunization was provided was higher among children aged 6 and younger (41.1%) than children and adolescents aged 7 -18 (17.1%). (Estimates from the Public Use File)

DATA TIP OF THE MONTH

Did you know…

To make estimates at the physician level pdf icon[PDF – 1.19 MB] the PHYSWT variable can be used. When running physician-level analysis, it is recommended that only records with a PHYSWT greater than zero be selected; this will give the correct sample counts and will not affect estimation of variance. Beside generating estimates for physician characteristics at the physician level, the addition of PHYSWT allows you to link visit data with physician data.

NEW PRODUCTS RELEASED THIS MONTH

  • Diagnosis Master Category List, 2016 pdf icon[PDF – 444 KB] – The Ambulatory and Hospital Care Statistics Branch is pleased to release the diagnosis categories table. The table displays diagnosis categories according to the 2016 National Center for Health Statistics, Division of Health Care Statistics, Diagnosis Master Category List, a classification scheme that can be used across inpatient and ambulatory settings when analyzing diagnosis data.

DATA TELL STORIES 

Tell Us Yours! How have you used information from the National Ambulatory Medical Care Survey or the National Hospital Ambulatory Medical Care Survey? Email us a brief description at ambcare@cdc.gov. In the subject field of your email, write “My NAMCS/NHAMCS data use example”. Your examples will help us showcase the value of NAMCS and NHAMCS.

 

June 2019

STATS OF THE MONTH

In recognition of Alzheimer’s & Brain Awareness Month (June 1-30) we present estimates for Alzheimer’s disease and dementia from the 2016 National Ambulatory Medical Care Survey (NAMCS).

  • In 2016, patients with Alzheimer’s disease or dementia documented in the medical record accounted for 0.7% of all office-based physician visits. Visits by patients with Alzheimer’s disease or dementia increased with age. Only 0.4% of visits made by patients aged 45-64 and 0.8% visits made by patients aged 65-74 had Alzheimer’s disease or dementia in the medical record whereas 3.5% of visits made by patients aged 75 and over had Alzheimer’s disease or dementia in the medical record. (Estimates from Table 18 pdf icon[PDF – 793 KB])

In recognition of National Safety Month (June 1-30) we present estimates for injury visits to emergency departments (ED), from the 2016 National Hospital Ambulatory Medical Care Survey (NHAMCS).

  • In 2016, injury visits accounted for 29.0% of all ED visits. There were approximately 42 million injury visits to the ED representing a rate of 13.3 visits per 100 persons. Visit rates by Black or African American persons were higher than visit rates by White persons (20.4 versus 13.1 visits per 100 persons). (Estimates from Table 15 pdf icon[PDF – 738 KB])

DATA TIP OF THE MONTH

Did you know…

NAMCS and NHAMCS are national probability sample surveys that use stratified, multistage sampling designs.  That is, visits are always clustered within providers and providers are sometimes clustered within geographic primary sampling units.  The sampling design affects the standard errors of estimates based on data collected from the sample.  Therefore, data users should always calculate standard errors for the survey estimates using statistical software that takes the complex sampling design into account.  Such software includes SUDAAN, SAS (SURVEYFREQ and SURVEYMEANS procedures), Stata, and SPSS Complex Samples, among others. Make sure all of the sample records – and not just those in a subset of the sample – are included in the analysis in order to obtain the best variance estimates.  This can be accomplished with a SUBPOPN statement in SUDAAN, or by using the DOMAIN statement in SAS, for example.

NEW PRODUCTS RELEASED THIS MONTH

DATA TELL STORIES 

Tell Us Yours! How have you used information from the National Ambulatory Medical Care Survey or the National Hospital Ambulatory Medical Care Survey? Email us a brief description. In the subject field of your email, write “My NAMCS/NHAMCS data use example”. Your examples will help us showcase the value of NAMCS and NHAMCS.

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Page last reviewed: June 17, 2020