title: Ascertainment of outpatient visits by patients with diabetes: The National Ambulatory Medical Care Survey (NAMCS) and the National Hospital Ambulatory Medical Care Survey (NHAMCS).
abstract: OBJECTIVE
  To estimate and evaluate the sensitivity and specificity of providers' diagnosis codes and medication lists to identify outpatient visits by patients with diabetes.
  
  
  METHODS
  We used data from the 2006 to 2010 National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey. We assessed the sensitivity and specificity of providers' diagnoses and medication lists to identify patients with diabetes, using the checkbox for diabetes as the gold standard. We then examined differences in sensitivity by patients' characteristics using multivariate logistic regression models.
  
  
  RESULTS
  The checkbox identified 12,647 outpatient visits by adults with diabetes among the 70,352 visits used for this analysis. The sensitivity and specificity of providers' diagnoses or listed diabetes medications were 72.3% (95% CI: 70.8% to 73.8%) and 99.2% (99.1% to 99.4%), respectively. Diabetic patients ≥75 years of age, women, non-Hispanics, and those with private insurance or Medicare were more likely to be missed by providers' diagnoses and medication lists. Diabetic patients who had more diagnosis codes and medications recorded, had glucose or hemoglobin A1c measured, or made office- rather than hospital-outpatient visits were less likely to be missed.
  
  
  CONCLUSIONS
  Providers' diagnosis codes and medication lists fail to identify approximately one quarter of outpatient visits by patients with diabetes.
authors.affiliation: Department of Preventive Medicine, The University of Tennessee Health Science Center, 66N. Pauline St., Ste. 633, Memphis, TN 38111, USA; Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, The University of Michigan, 1000 Wall St., Brehm Center Room 6111, Ann Arbor, MI 48105-5714, USA. Electronic address: kasao@uthsc.edu.
authors.forename: Keiko
authors.initials: K
authors.lastname: Asao
authors.affiliation: Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, The University of Michigan, 1000 Wall St., Brehm Center Room 6111, Ann Arbor, MI 48105-5714, USA. Electronic address: lmattei@med.umich.edu.
authors.forename: Laura N
authors.initials: LN
authors.lastname: McEwen
authors.affiliation: Child Health Evaluation and Research Unit, Division of Pediatric Endocrinology, The University of Michigan, 300 North Ingalls St., Room 6E18, Ann Arbor, MI 48109-5456, USA. Electronic address: joyclee@med.umich.edu.
authors.forename: Joyce M
authors.initials: JM
authors.lastname: Lee
authors.affiliation: Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, The University of Michigan, 1000 Wall St., Brehm Center Room 6111, Ann Arbor, MI 48105-5714, USA; Department of Epidemiology, The University of Michigan, 1000 Wall St., Brehm Center Room 6108, Ann Arbor, MI 48105-5714, USA. Electronic address: wherman@med.umich.edu.
authors.forename: William H
authors.initials: WH
authors.lastname: Herman
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000553:Ambulatory Care; D001786:Blood Glucose / Q000032:analysis; D000068240:Data Anonymization; D003920:Diabetes Mellitus / Q000097:blood / Q000188:drug therapy / Q000453:epidemiology / Q000628:therapy*; D016903:Drug Monitoring; D011307:Drug Prescriptions; D057286:Electronic Health Records; D005260:Female; D006442:Glycated Hemoglobin / Q000032:analysis; D019538:Health Care Surveys; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use; D038801:International Classification of Diseases; D008297:Male; D008875:Middle Aged; D058007:Physicians, Primary Care; D015995:Prevalence; D011320:Primary Health Care; D014481:United States / Q000453:epidemiology; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; C517652:hemoglobin A1c protein, human
keywords: Diabetes mellitus; Diagnosis codes; Medications; Sensitivity; The National Ambulatory Medical Care Survey (NAMCS); The National Hospital Ambulatory Medical Care Survey (NHAMCS)