SHORT-TERM COMPLIANCE WITH PEAK FLOW MONITORING - RESULTS FROM A STUDY OF INNER-CITY CHILDREN WITH ASTHMA

The objective of the study was to assess the feasibility of initiating daily peak flow monitoring in a research study of asthma in inner cit y children. We performed a descriptive study of patterns of peak flow monitoring in children randomized to receive a simple mini-Wright (SM) or an electronic recording meter (ERM). The ERM served as a ''covert' ' meter, providing objective documentation of actual peak flow use. Si xty-five Hispanic or African-American children, ages 5-9 years, with a history of physician-diagnosed asthma participated in the study. All children resided in census tracts with 40% or more of the population l iving at or below the poverty level. Subjects were instructed to use a peak flow meter (the SM or ERM) at least twice daily over a 3 week pe riod, and to record peak flow values in a paper diary. Subjects who re ceived the ERM were not made aware that measurements were also recorde d electronically. Differences in patterns of use of the SM and ERM wer e assessed with the Wilcoxon signed rank test and Wilcoxon sum rank te st. Adherence to peak flow monitoring was evaluated by comparing the p ercent days with missing values in the manually completed diary with t hose obtained by computer record. The Friedman statistic was used to c ompare changes in compliance (percent of days with missing peak flow e ntries) over time. Accuracy of peak flow readings was assessed by comp aring the manual and electronic recordings with paired and unpaired t- tests and with Pearson product moment correlations. The percent of day s with missing peak flow entries on diaries increased from 1.4% to 10. 6% from the first to third week of monitoring (P < 0.004). The ERMs in dicated a significantly greater percent of missing data than did the m anual records (P < 0.0002). The difference in the percent of missing d ata for the electronic and manual records was most notable during the third study week, when the ERM and the manually completed records indi cated that 52% and 15% of days, respectively, were without peak flow m easures. Large inter-subject variations in the relationship between ma nually and electronically recorded peak flow measurements were observe d, suggesting that errors in reading and transcribing peak flow rates occur in a subset of asthmatics. We conclude that children and caretak ers in the inner city may have considerable difficulty initiating and maintaining peak flow recordings. Data obtained by manual records may considerably overestimate actual use. Compliance with monitoring decre ases markedly between the first and third week of monitoring. (C) 1996 Wiley-Liss, Inc.