Comparing Definitions of Current and Active Asthma: An Analysis of BRFSS Asthma Call-back Survey (ACBS) Data

Transcription

1 Comparing Definitions of Current and Active Asthma: An Analysis of BRFSS Asthma Call-back Survey (ACBS) Data Cara Person, MPH, CPH CSTE Conference June 5, 2012 National Center for Environmental Health; National Center for Health Statistics Air Pollution and Respiratory Health Branch

2 Overview Asthma Definitions Asthma Call-back Survey Background Project Objectives Methods Results Conclusions Survey Research Implications

3 Confirmed: N/A CSTE Definitions Surveillance/Prevalence Probable: Yes Response to Ever Asthma and Still Asthma or Prescription Meds or Wheeze Episode Possible: Yes Response to OTC meds or Wheeze episode

4 Asthma Call-back Survey One-of-a-kind survey to: Monitor a common, costly chronic disease Represents 37 states (including DC and Puerto Rico) 2 Asthma definitions: Current, Active

5 Current Asthma Asthma Definitions Active Asthma Have you ever been told by a doctor or other health professional that you have asthma? Do you still have asthma? Last talked to a doctor (within past yr.)? Last took asthma medication (within past yr.)? Last had any symptoms (within past yr.)?

6 Objectives 1) To characterize differences in adult respondents classified as having current and active asthma 2) To make recommendations for defining asthma status

7 Methods Part I Compared current asthma status to active asthma status based on: Demographics, asthma attacks, health care utilization, activity limitation, co-morbidities Characterized persons classified as active asthma among former Determined spread across meds, symptoms, talked to MD Compared former active asthma status to former inactive status

8 Current vs. Active Asthma Current Asthma Yes (Current) No (Former) Active Asthma Yes (Active) 31,009 3,660 No (Inactive) 1,656 8,953

9 Asthma Definitions Flow Chart Ever Asthma = 46,291 Still Have Asthma 3 Last Questions Current = 32,665 Former = 12,613 Active = 34,669 Inactive = 10,609

10 Current Asthma Active Asthma Wgt. % 95% CI Wgt. % 95% CI Age Group (yrs.): ( ) 13.5 ( ) ( ) 18.5 ( ) ( ) 18.0 ( ) ( ) 19.5 ( ) ( ) 15.3 ( ) ( ) 15.3 ( ) Sex : Male 37.0 ( ) 37.2 ( ) Female 63.0 ( ) 62.8 ( ) Race/Ethnicity: White, NH 74.6 ( ) 73.3 ( ) Black, NH 8.8 ( ) 8.5 ( ) Hispanic 9.8 ( ) 11.3 ( ) Other, NH 4.2 ( ) 4.0 ( ) Multiracial, NH 2.6 ( ) 2.8 ( )

11 Current Asthma Active Asthma Wgt. % 95% CI Wgt. % 95% CI Education Less than High School 10.5 ( ) 10.4 ( ) High School Grad 25.7 ( ) 26.0 ( ) Some College/Tech 28.5 ( ) 28.2 ( ) College/Tech Grad 35.4 ( ) 35.4 ( ) Income Less than $15, ( ) 14.2 ( ) $15,000 to $24, ( ) 16.1 ( ) $25,000 to $49, ( ) 23.8 ( ) $50,000 to $74, ( ) 15.3 ( ) $75, ( ) 30.6 ( )

12 Results: Asthma Attacks Current Asthma Active Asthma Wgt. % 95% CI Wgt. % 95% CI Asthma Attack/Episode (12 months) 57.8 ( ) 55.3 ( ) Time Since Diagnosis < 12 months 2.9 ( ) 3.3 ( ) 1 5 years 11.6 ( ) 12.0 ( ) > 5 years 85.8 ( ) 84.7 ( )

13 Results: Activity Limits Current Asthma Active Asthma Wgt. % 95% CI Wgt. % 95% CI Activity Limitation None 41.6 ( ) 44.2 ( ) Some 40.8 ( ) 39.3 ( ) A lot 17.6 ( ) 16.5 ( ) Missed Days 33.5 ( ) 32.1 ( )

14 Results: Health Care Utilization Current Asthma Active Asthma Wgt. % 95% CI Wgt. % 95% CI Insurance 87.9 ( ) 87.8 ( ) Emergency Room Visit 17.7 ( ) 16.4 ( ) Urgent Care Visit 23.9 ( ) 23.2 ( ) Hospital Visit 5.6 ( ) 5.4 ( )

15 Results: Co-morbidities Current Asthma Active Asthma Wgt. % 95% CI Wgt. % 95% CI COPD 12.6 ( ) 12.1 ( ) Emphysema 8.0 ( ) 7.8 ( ) Chronic Bronchitis 29.4 ( ) 29.1 ( ) Depression 34.4 ( ) 34.3 ( )

16 Results: Current vs. Active Asthma Use of the current vs. active asthma definition does not produce differences in responses to survey questions that were statistically significant*. More people were captured by the active asthma definition.

17 Asthma Definitions Flow Chart Ever Asthma = 46,291 Still Asthma Question 3 Last Questions Current = 32,665 Former = 12,613 Active = 34,669 Inactive = 10,609 Former/Active = 3,660 Former/Inactive = 8,953

18 Current vs. Active Asthma Current Asthma Yes (Current) No (Former) Active Asthma Yes (Active) 31,009 3,660 No (Inactive) 1,656 8,953

19 Former Active Asthma N = 3,660 Medication Use (40.8%) Recent Symptoms (65.3%) Active Asthma Talking with a Doctor (57.5%)

20 Former Active Asthma N = 3,660 Talk with a Doctor None - 21 <1 year - 2,087 1 year + - 1,524 Medication Never < 3 months mos. /< 1 yr yr. - 1,941 Symptoms Never - 38 < 3 months - 1,361 3 mos. /< 1 yr. - 1,030 1 yr. - 1,154

21 Former Asthma Active Inactive P-values Weighted % Weighted % Age Group (yrs.): < <.001 Sex : Male <.001 Female <.001 Race/Ethnicity: White, NH Black, NH Hispanic <.001 Other, NH Multiracial, NH

22 Education Less than High School Former Asthma Active Inactive P-values Weighted % Weighted % High School Grad Some College/Tech College/Tech Grad Income Less than $15, $15,000 to $24, $25,000 to $49, $50,000 to $74, $75,

23 Results: Asthma Attacks Former Asthma Active Inactive P-values Weighted % Weighted % Asthma Attack/Episode (12 months) Time Since Diagnosis <.001 < 12 months < years <.001 > 5 years <.001

24 Results: Activity Limitation Former Asthma Active Inactive P-values Weighted % Weighted % Activity Limitation None Some A lot Missed Days <.001

25 Results: Health Care Utilization Former Asthma Active Inactive Weighted % Weighted % Insurance Emergency Room Visit 5.9 N/A Urgent Care Visit 11.1 N/A Hospital Visit 1.8 N/A

26 Results: Co-morbidities Former Asthma Active Inactive P-values Weighted % Weighted % COPD <.001 Emphysema <.001 Chronic Bronchitis <.001 Depression <.001

27 Results Part I: Former Active vs. Former Inactive Asthma There was a statistically significant difference in the percent of respondents between groups for the following variables: 25-34, year olds, males, females, Non Hispanic whites, Hispanics, HS and College graduates, Income $75,000+ Asthma attacks Time since diagnosis Missed Days Co-morbidities

28 Conclusions Part I Examining respondents patterns of responses to multiple questions identifies more persons with asthma Former asthma respondents categorized as active asthma may not interpret the still question the way it was intended

29 Asthma Definitions Flow Chart Ever Asthma = 46,291 Still Have Asthma 3 Last Questions Don t Know Current = 32,665 Former = 12,613 Active = 595 Inactive = 391

30 Methods Part II Calculated sensitivity and specificity between asthma definitions using current asthma definition as the gold standard Calculated kappa statistic: To determine agreement between definitions To identify the added value of each active asthma definition question

31 Current vs. Active Asthma Current Asthma Active Asthma Yes (Current) A No (Former) B Yes (Active) 31,009 3,660 No (Inactive) 1,656 8,953 C D

32 Sensitivity: Proportion who truly have disease, identified by measurement tool A 31,009 95% A +C (31, ,656) Specificity: Proportion who truly do not have the disease, identified by measurement tool D 8,953 71% B + D (8, ,660)

33 Results Part II: Sensitivity and Specificity of Asthma Definitions Sensitivity Specificity

34 Results Part II: Kappa Statistic Agreement Asthma Definition Kappa Statistic Current.69 Current + Meds.76 Current + MD.80 Current + Sxs.82 Current + Meds + MD.84 Current + Meds + Sxs.84 Current + MD + Sxs.90 Current + Meds + MD + Sxs.91

35 Conclusions Part II Adding 3 active asthma questions maintains sensitivity, but improves specificity (100%) Current asthma definition + symptoms question adds the largest group of respondents missing from current asthma definition

36 Survey Research Implications Part I No significant change in results using current vs. active asthma definition Continued use of current definition is recommended because: Historical data are available Only 2 questions are needed vs. 4 for active asthma ( Ever Asthma question) Comparison data are available in other national surveys

37 Survey Research Implications Part II The active asthma definition is a better indicator for analysis of: Asthma characteristics Co-morbidities Specific outcomes

38 Acknowledgements Cathy Bailey Michael King Jeanne Moorman Hatice Zahran

39 Contact information For more information please contact Centers for Disease Control and Prevention 1600 Clifton Road NE, Atlanta, GA Telephone, CDC-INFO ( )/TTY: Web: The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention. National Center for Environmental Health Division of Environmental Hazards and Health Effects