A drug therapy problem (DTP) is any undesirable event experienced by a patient that accompanies drug therapy, prevents the patient from achieving their desired therapeutic goals, and requires expert judgment to resolve (Cipolle et al., 2012). Globally, DTP has increased significantly over the past few decades (Nivya et al., 2015). During the course of medication use, from prescription to follow-up treatment, DTP may occur at any time (Viktil and Blix, 2008; Cipolle et al., 2012). Worldwide, more than half of all medicines are prescribed and dispensed inappropriately, and half of the patients fail to take them correctly (World Health Organization, 2002; Bigdeli et al., 2015).

Unnecessary drug therapy, need additional drug therapy, ineffective drug therapy, dosage too low, adverse drug reactions, dosage too high, and non-adherence are seven types of drug therapy problems that fall under four patients’ drug-related needs (Cipolle et al., 2012). The risk of medication-related harm is three times greater for children than for adults (Kaushal et al., 2001). Each organ system, such as the liver and kidneys which play key roles in drug metabolism and excretion, is immature in the pediatric population (Maheshwari et al., 2019). The maturity of organ function and body composition can significantly impact the pharmacokinetics of various drugs (Kearns et al., 2003; Maheshwari et al., 2019). Medication errors are a significant problem for pediatric patients (Wong et al., 2009).

The higher likelihood of DTP among children is due to the different steps involved in calculating, reviewing, preparing, and administering doses, and the increased complexity in the approach to drugs used for children (Wong et al., 2009; Bereda, 2022). There is a greater risk of harm when pediatric medicines are optimized without robust trial data or appropriate medication formulations (Benn, 2014). To provide safe and effective drug therapy for children, it is imperative to understand and integrate the role growth and development plays in drug disposition and actions (Kearns et al., 2003). It is important to realize that absorption, distribution, metabolism, and excretion processes change throughout growth and development, so extrapolation can either lead to an overestimation or underestimation of the dose required for treatment (O'Hara et al., 2015).

Drug therapy problems have a significant impact on patient clinical outcomes, leading to reduced quality of life, higher morbidity and mortality, hospital admissions, long hospital stays, a considerable increase in the demand for additional drugs, and an increased healthcare cost burden on patients and the government (Easton et al., 2004; Viktil and Blix, 2008; Hoonhout et al., 2009; Elliott et al., 2018). Different studies have revealed a considerable proportion of drug-related visits and hospitalizations, although the majority are preventable (Commission, 2009; Braun et al., 2012; Al-Azzam et al., 2016; Feyissa et al., 2020).

Various factors contribute to the occurrence of DTP. These include polypharmacy, certain infectious and parasitic diseases, length of hospital stay, number of diseases, and number of drugs per patient (Rashed et al., 2014; Birarra et al., 2017; Meknonnen et al., 2017). It is critical to detect and classify DTP to provide relevant solutions and achieve desired outcomes at the lowest possible cost (Gelchu and Abdela, 2019). The remedies for identified DTPs include changing drug products or their doses, educating the patients on how to maximize medication effectiveness, and developing a care plan of individualized goals of therapy for each patient (Hepler and Strand, 1990).

Most previous studies have focused on one element of DTP, such as adverse drug reactions (ADRs) or dosing. Consequently, the findings of such investigations are insufficient to portray the full picture of DTP. Moreover, evidence of DTP among admitted pediatric patients is limited in low-income settings. Therefore, the current study aimed to assess the prevalence of DTP and associated factors among pediatric patients admitted to WSUCSH by considering all aspects of DTP. The findings of this study will benefit patients, practitioners, health institutions, and policymakers. It can also be used as a tool to empower pharmaceutical care services and promote the importance of clinical pharmacists in the hospital’s pediatric units.

The medical records of 369 pediatric patients admitted to the WSUCSH between 8 July 2020, and 7 July 2021, were reviewed, and two records were excluded because of poor data quality (Figure 1).

Prior studies have assessed drug therapy problems, focusing mainly on one aspect. However, the current study at the WSUCSH estimated the prevalence of drug therapy problems in admitted pediatric patients by assessing most of its elements. Investigation of DTP considering most of its elements will assist in developing a holistic intervention approach to counter the occurrence of DTP among admitted pediatric patients. In this study, 281 DTPs were identified resulting in the overall prevalence of DTP to be 60.2%. Moreover, the number of disease conditions, polypharmacy, and duration of hospital stay were independent predictors of drug therapy problems.

The overall prevalence of drug therapy problems was 60.2% (95% CI:55.2%, 65.2%). This finding illustrates that a substantial number of pediatric patients admitted to the WSUCSH have encountered drug therapy problems. The prevalence of DTP in the current setting is higher than that in previous studies conducted at Zewdtu Memorial Referral Hospital in Addis Ababa, KAMC-Jeddah, and Hong Kong, which reported DTP prevalence rates of 31.57%, 35.9%, and 21%, respectively (Rashed et al., 2014; Birarra et al., 2017; AlAzmi et al., 2019). DTPs were classified using different methods, which may account for this difference. We employed Cipolle’s classification method, while studies in Addis Ababa (Birarra et al., 2017) and Hong Kong (Rashed et al., 2014) employed the Pharmaceutical Care Network Europe (PCNE) classification system. Moreover, the observed difference might be due to disparities in the healthcare systems and practitioners across countries.

Regarding the categories of DTPs, need additional drug therapy was the most common DTP in this investigation, accounting for 50% of the total DTPs. This finding regarding the need for additional drug therapy for DTP is higher than that reported in previous studies in Ethiopia. A study in Mettu Karl Referral Hospital (MKRH) reported 25.09% (Bekele et al., 2021), whereas another study in a pediatric ward of Dessie Referral Hospital reported 25.2% (Bizuneh et al., 2020). This is also higher than that reported in Hong Kong (3.7%) (Rashed et al., 2014). A possible explanation for this difference could be the variation in the level of knowledge and experience of the health professionals at these health facilities concerning the appropriate indication for drugs and the proper choice of drugs based on observed cases. Furthermore, comorbidities and patient conditions may have contributed to these differences.

In the current investigation, dose too low was responsible for 28.5% of the identified DTPs. This was higher than the results reported in Brazilian and Hong Kong studies, which found doses too low to be 13.1% and 19.5%, respectively (Rashed et al., 2014; Nascimento et al., 2020). This finding is consistent with that of a prospective observational study conducted at Jimma University Medical Center (JUMC), which reported 27.52% (Feyissa Mechessa et al., 2020). This study showed that low doses were more common in hospitalized pediatric patients, which might be due to improper weight-based dose calculations and frequency of administration. On the other hand, the DTP category identified in this study, the 3.9% dose too high, which is lower than the 15.9% and 16.1% findings from studies conducted in Hong Kong and Saudi Arabia, respectively (Rashed et al., 2014; AlAzmi et al., 2019).

In this study, unnecessary drug therapy was 11.7%, which aligns with the 16.8% reported in a study conducted in the pediatric ward of Dessie Referral Hospital, Ethiopia (Bizuneh et al., 2020). This showed that a considerable proportion of patients were given unnecessary medications, which might have resulted in adverse drug reactions and additional medication-related costs. Therefore, it is worthwhile to avoid unnecessary drug therapy and improve deprescribing practices to improve treatment outcomes in hospitalized patients. In the present study, 6.1% of the DTPs were found to be ineffective drug therapy. This is in line with that of Dessie’s study, 2.5% (Bizuneh et al., 2020), but lower than the 49% reported in the Brazilian study among cardiac neonates under intensive care (Nascimento et al., 2020).

As revealed in this study, the duration of hospital stay was significantly associated with drug therapy problems, with higher odds of drug therapy problems among pediatric patients who stayed 6–10 days hospitalized. This is consistent with Ethiopian studies conducted at Jimma University Medical Center, Metu Karl Referral Hospital, and Nekemte Referral Hospital (Dedefo et al., 2016; Feyissa Mechessa et al., 2020; Bekele et al., 2021). A possible explanation is that the more patients stay in the hospital, the greater the risk of hospital-acquired (nosocomial) infections, making drug regimens more complex. Complex drug regimens are risk factors for administration errors and nonadherence (Pantuzza et al., 2017; Schmidt et al., 2020); thus, early and accurate identification of the patient’s condition is crucial for reducing hospital stay. Efficient and comprehensive diagnostic procedures enable healthcare professionals to achieve this goal. In addition, adherence to the recommended treatment guidelines while prescribing the drug frequency and dose would be worthwhile.

A significant association was also found between polypharmacy and DTP. The likelihood of DTP was three times higher in patients with polypharmacy than in their counterparts. This finding is in agreement with the study conducted in Addis Ababa and Jimma on DTP, which reported that patients on polypharmacy have a complex drug schedule that may contribute to poor medication compliance, adverse drug effects, potential drug-drug interactions, and increased risk of DTP occurrence (Birarra et al., 2017; Feyissa Mechessa et al., 2020). Primary care physicians can address problems of polypharmacy by considering deprescribing, a set of interventions to identify inappropriate or unnecessary medications, and discontinuing them, as an essential part of good prescribing (Endsley, 2018; Farrell and Mangin, 2019). The involvement of clinical pharmacists in multidisciplinary care teams may lead to better treatment outcomes by providing informed decision-making.

In the present study, the number of disease conditions was an independent predictor of DTP. Those who had three or more disease conditions were two times more likely to encounter DTP than those who had fewer conditions. This is corroborated by previous studies on DTP that have identified the number of disease conditions as major predictors of DTP (Feyissa Mechessa et al., 2020; Bekele et al., 2021). The more health conditions you have, the more likely you are to take more than one type of prescription drug to manage them. There is a risk of drug-drug or drug-disease interactions. These interactions could lower the effectiveness of the drug in patients.

Improved pharmaceutical care services, which engage clinical pharmacists in the study setting, might minimize drug therapy problems in the pediatric population. An appropriate type of medication and prescribed doses may be tailored to the patient’s needs when clinical pharmacists collaborate with prescribing physicians. Optimizing medication dosages for the pediatric population could significantly reduce certain identified DTPs and this could be a prospect of our study.

The current study used a standardized DTP identification tool that was evaluated and accepted by experts, but it is not without limitations. Although we attempted to investigate all categories of drug therapy problems, adverse drug reactions, and patient adherence were not included because of the retrospective study design constraints and poor documentation trends in the current setting for these two categories of DTPs. The retrospective design employed in the current study did not allow for the assessment of two categories of DTPs. This limitation might have affected the overall observed prevalence of DTPs.

Furthermore, since the study was conducted at a single center, WSUCSH, it may not have successfully represented the diversity of the population that could have been achieved in a multicenter setting. This limitation potentially affects the generalizability of the study’s results. Whenever practitioners translate the current findings to their setting, they should carefully consider limitations to the external validity that may arise from a single-center study. Therefore, future studies should consider a multicenter prospective study design that enables the inclusion of a diverse population and comprehensive data collection across all categories of DTPs.

The current study showed that the majority of pediatric patients admitted to the WSUCSH had at least one drug therapy problem, indicating that optimal medication management in pediatric patients remains a major challenge in clinical practice. Need additional drug therapy was the most common DTP identified followed by a dose too low. The number of disease conditions, polypharmacy, and duration of hospital stay were independent predictors of drug therapy problems. Enhancements to pharmaceutical care services, optimized dosage practices, improved deprescribing by clinicians, and efficient, comprehensive diagnostic procedures have the potential to reduce specific drug therapy problems in hospitalized pediatrics significantly.