Association between continuity of care and inappropriate prescribing in outpatient care in Germany: a cross-sectional analysis conducted as part of the LoChro trial

Abstract

Objectives: Potentially inappropriate medications (PIMs) and potential prescribing omissions (PPOs) are common in multimorbid patients. This study aims to describe PIMs and PPOs in an open-access outpatient setting and to investigate any association between continuity of care (CoC) and PIMs and PPOs in multimorbid older patients.

Design: Cross-sectional study using patient-confirmed outpatient medication plans to describe PIMs and PPOs using the 'Screening Tool of Older Person's Prescription/Screening Tool to Alert to Right Treatment' version 2. Four Poisson regressions modelled the number of PIMs and PPOs using context-adapted versions of the Usual Provider of Care (UPC) and the Modified Modified Continuity Index (MMCI) as measures for CoC.

Setting: Southern Germany, outpatient setting.

Participants: 321 participants of the LoChro-trial at 12-month follow-up (both arms). The LoChro-trial compared healthcare involving an additional care manager with usual care. Inclusion criteria were age over 64, local residence and scoring over one in the Identification of Older patients at Risk Screening Tool.

Primary outcomes: Numbers of PIMs and PPOs.

Results: The mean number of PIMs was 1.5 (SD 1.5), lower than the average number of PPOs at 2.9 (SD 1.7). CoC showed similar results for both indices with a mean of 0.548 (SD 0.279) for MMCI and 0.514 (SD 0.262) for UPC. Both models predicting PPOs indicated more PPOs with higher CoC; statistical significance was only demonstrated for MMCI (MMCI~PPO: Exp(B)=1.42, 95% CI (1.11; 1.81), p=0.004; UPC~PPO: Exp(B)=1.29, 95% CI (0.99; 1.67), p=0.056). No significant association between PIMs and CoC was found (MMCI~PIM: Exp(B)=0.72, 95% CI (0.50; 1.03), p=0.072; UPC~PIM: Exp(B)=0.83, 95% CI (0.57; 1.21), p=0.337).

Conclusion: The results did not show a significant association between higher CoC and lesser PIMs. Remarkably, an association between increased CoC, represented through MMCI, and more PPOs was found. Consultation of different care providers in open-access healthcare systems could possibly ameliorate under-prescribing in multimorbid older patients.

Trial registration: German Clinical Trials Register (DRKS): DRKS00013904.

Keywords: general medicine (see internal medicine); geriatric medicine; health services; multimorbidity; patient care management; polypharmacy.

Figure 1. Flow diagram of the LoChro-study. *Reasons for exclusion: not met inclusion criteria (n=1,477) or refused participation (n=720); **patient and proxy assessments; ***only complete datasets were included with sufficient information concerning medication regimes, diagnosis and CoC; pilot datasets were excluded. CoC, continuity of care; PIM, potentially inappropriate medication; PPO, potential prescribing omission.

Figure 2. Frequencies of potentially inappropriate medication (PIM) according to STOPP/START criteria version 2 with an absolute frequency of at least 10 for the study population at LoChro-T1-follow-up (n=321). Percentage proportions of the total number of PIMs in brackets. PIM D15 was assessed as an additional criterion. PIM B8: electrolyte imbalances here specifically hypokalaemia, hyponatraemia, hypercalcaemia. PPI, proton pump inhibitor; TCA, tricyclic antidepressants.

Figure 3. Frequencies of potential prescribing omissions (PPO) according to STOPP/START criteria version 2 with an absolute frequency of at least 10 for the study population at LoChro-T1-follow-up (n=321). Percentage proportions of the total number of PPOs in brackets. PPO A5: unless the status is end-of-life or age >85 years. PPO F1: with renal disease. PPO C6: if the exclusion of iron deficiency and renal failure. AF, atrial fibrillation; AT blocker, angiotensin receptor blocker; COPD, chronic obstructive pulmonary disease; DMARD, disease modifying anti-rheumatic drug.