Reliability and validity of the Swedish indicator 'Drugs that should be avoided in older people'-an appraisal of a set of potentially inappropriate medications

Abstract

Purpose: To analyse the reliability and validity of the Swedish indicator 'Drugs that should be avoided in older people'.

Methods: From a previous study that included consecutive primary care patients ≥ 65 years of age, all patients ≥ 75 years of age were analysed. Two physicians independently screened their medication lists and medical records, applying the Swedish indicator which includes potentially inappropriate medications (PIMs): long-acting benzodiazepines, drugs with anticholinergic action, tramadol, propiomazine, codeine, and glibenclamide. The clinical relevance of identified PIMs was independently assessed. Thereafter, the physicians determined in consensus whether some medical action related to the drug treatment was medically justified and prioritised before the next regular visit. If so, the drug treatment was considered inadequate, and if not, adequate.

Results: A total of 1,146 drugs were assessed in 149 patients (75‒99 years, 62% female, 0‒20 drugs per patient). In 29 (19%) patients, at least one physician identified ≥ 1 PIM according to the indicator at issue; 24 (16%) patients were concordantly identified with ≥ 1 such PIM (kappa: 0.89). Of 26 PIMs concordantly identified, the physicians concordantly assessed four as clinically relevant and 12 as not clinically relevant (kappa: 0.17). After the consensus discussion, six (4%) patients had ≥ 1 PIM according to the studied indicator that merited action. Using the area under the receiver operating characteristic (ROC) curve, the indicator did not outperform chance in identifying inadequate drug treatment: 0.56 (95% confidence interval: 0.46 to 0.66).

Conclusion: The Swedish indicator has strong reliability regarding PIM detection but does not validly reflect the adequacy of drug treatment.

Keywords: Aged; Inappropriate prescribing; Older people; Potentially inappropriate medications; Swedish indicator.

Fig. 1

Overview of the assessments performed in the present study^a, as well as the results. ^aDetection and clinical relevance assessment of potentially inappropriate medications (PIMs), as well as of potential prescribing omissions (PPOs), was performed systematically in the original studies [16, 17] using three screening tools: STOPP/START [18], EU-7(PIM) list [6], and all PIMs/PPOs included in the Swedish set [9]. ^bPIMs reported here are restricted to those in the Swedish indicator ‘Drugs that should be avoided in older people’ and among patients aged ≥ 75 years (see Table 5). ^cThere were 149 patients aged ≥ 75 years, of which 146 had drug treatment. ^dInadequate drug treatment was defined as follows: one or more actions related to the drug treatment would have been medically justified and prioritised before the next regular visit but were not carried out. The total number of patients with inadequate drug treatment (i.e. not only due to Swedish indicator) was n = 48

Fig. 2

Receiver operating characteristic (ROC) curves for the Swedish indicator ‘Drugs that should be avoided in older people unless specific reasons exist’ to identify the overall drug treatment as adequate or inadequate.^a For comparison, a ROC curve based on the number of drugs in the medication list (regular and as needed) is presented. The random classifier is denoted with a dashed line in grey. ^aReference standard: inadequate drug treatment defined as follows: one or more actions related to the drug treatment would have been medically justified and prioritised before the next regular visit but were not carried out, assessed in retrospect by two specialist physicians in consensus. Adequate drug treatment reflected the opposite, i.e. no additional action during the current visit related to the drug treatment would have been medically justified and prioritised before the next routine visit