Taylor Amelia, Chen Li-Chia, Smith Murray D
Division for Social Research in Medicines and Health, School of Pharmacy, The University of Nottingham, University Park, Nottingham, NG7 2RD, UK.
Int J Clin Pharm. 2014 Feb;36(1):112-9. doi: 10.1007/s11096-013-9862-0. Epub 2013 Dec 1.
Poor adherence to inhaled corticosteroids (ICS) is known as the main cause for therapeutic failure in asthma treatment and associated morbidity. To improve adherence, targetted and effective interventions need to be developed ideally based on using longitudinal follow-up of a large study cohort to establish patterns and influences on adherence.
To develop an annual measure of asthma patients' adherence to ICS using primary care prescribing data over consecutive annual intervals, and to statistically model ICS adherence controlling for a range of patient factors.
A retrospective cohort study between 1997 and 2010 using United Kingdom general practice prescribing data on asthma patients aged between 12 and 65 years, without a diagnosis of chronic obstructive pulmonary disease.
Patient's ICS prescriptions are used to calculate the 'number of days prescribed during calendar year' divided by 'number of days in the interval' to form an annual prescription possession ratio (PPR) for each patient. Several definitions of PPR are considered and compared when calculating numerator and denominator. Adherence, measured by the preferred PPR, is then modelled to estimate the effect of asthma exacerbation, severity, control and other patient factors on adherence.
PPR, being a proxy measure for adherence.
Annual PPR by all strategies gave a similar frequency profile. ICS were either over- or under-prescribed for over half of the follow-up time. Adherence was lower in younger patients, those newer to the study timeframe, those with less severe asthma, those with good control, with lower previous adherence, and who had not previously experienced an exacerbation.
The chosen PPR simulated clinical use of ICS most closely; including overlapping days, excess days passed to the next interval, considering gaps in the denominator, with censoring at 100 %. The PPR is a useful measure for signalling or measuring adherence changes over time. The modelling results identified many characteristics which would indicate which asthma patients and at what points in their treatment cycle they would be at increased risk of low adherence.
吸入性糖皮质激素（ICS）依从性差是哮喘治疗失败及相关发病率的主要原因。为提高依从性，需要制定有针对性的有效干预措施，理想情况下应基于对大型研究队列的纵向随访来确定依从性模式及影响因素。
利用连续年度间隔的初级保健处方数据制定哮喘患者对ICS依从性的年度测量方法，并对一系列患者因素进行统计学建模以控制ICS依从性。
一项回顾性队列研究，研究时间为1997年至2010年，使用英国全科医疗中12至65岁哮喘患者的处方数据，这些患者未被诊断为慢性阻塞性肺疾病。
使用患者的ICS处方计算“日历年规定天数”除以“间隔天数”，得出每位患者的年度处方持有率（PPR）。计算分子和分母时考虑并比较了PPR的几种定义。然后对通过首选PPR测量的依从性进行建模，以估计哮喘加重、严重程度、控制情况及其他患者因素对依从性的影响。
PPR，作为依从性的替代指标。
所有策略的年度PPR频率分布相似。在超过一半的随访时间里，ICS要么处方过量，要么处方不足。年轻患者、研究时间框架内新入组的患者、哮喘不太严重的患者、控制良好的患者、先前依从性较低的患者以及之前未经历过病情加重的患者，其依从性较低。
所选的PPR最接近ICS的临床使用情况；包括重叠天数、转入下一个间隔的多余天数、考虑分母中的间隔，且审查上限为100%。PPR是随时间发出信号或测量依从性变化的有用指标。建模结果确定了许多特征，这些特征可表明哪些哮喘患者以及在其治疗周期的哪些阶段依从性低的风险会增加。
