This study provided important information about the Medication regimen complexity index (MRCI) and medication adherence level among patients with multimorbidity. Evaluating medication regimen complexity has tried to determine its magnitude as well as its relationship with the level of medication adherence among multimorbid individuals. As these patient groups were at high risk of having high regimen complexity and low level of adherence, due to the presence of multiple chronic comorbidities and polypharmacy for the long durations; close follow-up of these patients could be warranted.
To the best of investigators knowledge, this is the first study that assessed MRCI and its association with medication adherence that account for the complexity of multiple medication intake in the daily life for patients with multimorbidity in low-income sub-Saharan African countries such as Ethiopia. Several studies also have investigated the factors associated with adherence to chronic medication (18, 19)
In the current study, MRCI complexity scores were stratified by low, medium, and high regimen complexity. The majority of participants had high complexity score. Dosing frequency contributed most to the MRCI across all of the three sections of pMRCI followed by dosage form and additional instruction. Studies revealed that the complexity of pharmacotherapy is composed of multiple features of the prescribed regimen including the number of different drugs in the treatment, number of doses of each drug per day, number of per-dose dosage units, the total number of doses per day and drug interactions with food (20). Consistently with the current study, a previous study (21) also showed that a comparable number of patients were in the same medication complexity burden score. In contrast, the current finding was higher than previous study done in Brazil (22). This discrepancy may be due to use of different cut-off points, the treatment approach of clinicians in line with guidelines, and the difference in socio-demographics of patients.
The current study has also demonstrated adherence level of patients to their medications based on the Adherence in Chronic Diseases Scale (ACDS), and the finding revealed that significant number of participants with multimorbidity had low level of adherence to their medications. Similarly, earlier studies done in Saudi Arabia (23), South India (24) and South Australia (25) showed that a significant number of study subjects have been in the level of low medication adherence. However, the finding was vary with the study done in Spain (26), which revealed that significant proportion of the study participants were in the range of high adherent level of medications. This variation potentially might be due to poor patients’ medication knowledge in the resource-limited setting and negative perceptions about medication, fear of side effects and high medication costs in patients with polypharmacy. In addition to this attributed to differences in the study setting, methods used to measure medication adherence, quality of service in the health facilities and physicians' approach to their patients that could bring differences in patients’ attitudes toward their medication.
The present study has identified the association of participants’ socio-demographic and clinical variables with the level of adherence. Consistently with the previous studies (27–31), the multivariable ordinal logistic model showed that monthly income, duration of the disease, Charlson comorbidity index (CCI) and the number of medications were found to have significant association with level of medication adherence in the current study. The Person Chi Square also showed that there is a significant association between medication regimen complexity and level of adherence. In contrast, a study in China (32) showed that age of the participants and alcohol drinking status were associated with level of adherence of medications. This difference could be attributed to the heterogeneity of the factors and relates to diseases, drugs and behavior that may affect the patient’s taking the drugs. For example, the treatment approach of clinicians and patients’ lifestyles may have a pivotal impact on the variability which might be relate with environmental and socio-cultural differences.
To better understand the complexity of adherence to multiple medications and in daily life, we need measures that can detect differences in adherence; between medications, individual persons and over time. An increasing number of patients with multimorbidity means that more and more patients are faced with complex medication regimens. Some of them including; the number of drugs, low-income level, duration of follow up and, the number of CCI were the only predictors of medication adherence in multimorbidity patients have been consistently shown to have a significant association (25, 32–35) On the other hand, participants’ age, level of education and social drug use (19, 36–38) were also associated with poor adherence. The difference could be due to variability in the study participants, adherence measurement tool, health care systems and policies, and knowledge, skill and patient care approaches of the health care professionals. This in turn is because; non-adherence is not limited to medication alone. It can also take many other forms, which include the failure to keep appointments, to follow recommended dietary or other lifestyle changes and to follow other aspects of treatment or recommended preventive health practices, which all can be the reason for the differences.
Consistently with the findings of the present study, another research conducted in Korea Hospital (39) showed that lower household income was significantly associated with increased odds of low level of adherence. The associated factor identified in this study was also largely consistent with findings with a previous large-scale territory-wide study using patient health records in the Chinese population (40) and Italian (41). Lower household income might be the reason of medication noncompliance due to affordability issues in patients with multimorbidity. However, studies done in Iran (42) showed that income was no significant association with medication adherence. We know that financial situation is an important determinant of health which negatively affecting health outcomes and contributing to health inequities. Patients with a lower income had a low level of adherence and low quality of life because most multimorbidity patients are medical treatment dependent and unable to afford treatment costs. Medication adherence is adversely affected by various factors such as patient-centered, therapy-related, social and economic, disease, and health care system factors (31). Hence, the identification of specific barriers for each patient and designing appropriate prevention strategies are indispensable to mitigate medication adherence.
In this finding treated with several medications (polypharmacy) was also significantly associated with non-adherence to medication. This is in line with the finding from Mangalore, in India (43). The association could be justifying those patients with polypharmacy may have poor medication adherence due to affordability issue and because of adverse effects related with potential drug-drug interactions. Therefore, patients with polypharmacy would be in close follow-up during in their course overtreatment. Medication non-adherence can happen potentially in patients with comorbidity have been taking polypharmacy for longer period of follow-up time. The numerous barriers to the effective use of medications in resources limited settings include; poor communication between the patient and physician, inappropriate and knowledge gap on medications, fears of adverse events, long-term therapy, polypharmacy, cost and access barrier (44).
Although medication regimen complexity and medication adherence are different outcome measures, it is believed that medication regimen complexity has been associated with non-adherence. The current study also disclosed that there is statistical relationship between medication regimen complexity and medication adherence level. Patients with multimorbidity have potentially treated with polypharmacy, which can be the reason of increased medication regimen complexity burden, in turn it could be result in poor medication adherence of patients with multimorbidity. Hence, patients with multimorbidity who have been treated with poly pharmacy could assess their level of medication regimen complexity and adherence level.
Strength and Limitation of the Study
Considering the recent burden of patients with multimorbidity; the present study has highlighted the level of medication regimen complexity and adherence, which is the first study in the study setting attempted to explore the burden of medication regimen complexity and its association with adherence in patients with multimorbidity management.
There were some limitations to the present study that need to be considered. First, it is a cross-sectional study design, whereby claims about the directionality of the causal relationship between the dependent and independent variables cannot be verified. Secondly, MRCI was calculated using only what was captured in the patients’ medical chart. As a result, any medications or instructions not recorded were missed out. Another limitation was the extent of generalizability may be limited, since it was a single-centered study. Despite the above limitations, we hope it might be a bench mark for the coming researchers in study area with larger population and follow-up study design. The finding from the current study may use as an input for clinicians, researchers and any stakeholders to their interest and context.