When can personal best peak flow be determined for asthma action plans?

Area of Science:

• Pulmonary Medicine
• Respiratory Health
• Clinical Trials

Background:

• Asthma action plans based on personal best peak expiratory flow (PEF) improve outcomes, unlike those based on predicted PEF.
• Guidelines recommend assessing personal best PEF over 2-3 weeks during stable asthma control.
• Optimal timing for personal best PEF assessment after treatment initiation or changes remains unclear.

Purpose of the Study:

• To determine the time required for personal best PEF to plateau during corticosteroid treatment in poorly controlled asthma.
• To evaluate the efficacy of budesonide treatment on PEF metrics.

Main Methods:

• Analysis of spirometric data from 61 subjects with poorly controlled asthma over 72 weeks.
• Calculation of average morning pre-bronchodilator PEF weekly.
• Definition of personal best PEF as the highest PEF in the preceding 2 weeks.
• Identification of time to plateau as the week of no further PEF improvement.

Main Results:

• Personal best PEF, determined by twice-daily monitoring, plateaued at 95% predicted after 3 weeks of budesonide.
• Baseline average morning PEF was 61% predicted, rising to a plateau of 95% predicted (p<0.0001).
• Average morning PEF and reliever use continued to improve for longer durations (3 and 7 months, respectively).

Conclusions:

• Personal best PEF, defined as the highest PEF over the prior 2 weeks, is valuable for asthma self-management.
• Twice-daily monitoring reveals that personal best PEF plateaus within weeks of initiating corticosteroid therapy.