Identification and resolution of drug therapy problems among hypertensive patients receiving care in a Nigerian-A pilot study

An event involving drug therapy that actually or potentially interferes with the desired health outcomes is known as drug therapy problem [1]. Drug therpy problems is de ined by the World Health Organization (WHO) as “any response to a drug which is noxious and unintended and which occurs at doses normally used in man for prophylaxis, diagnosis or therapy of disease, or for the modi ication of physiological function” [2]. Hypertension is the most common cardiovascular disease. In a surveyed carried out in 2009, hypertension was in 28% of American adults and 60% of adults 65 years or older [1]. The prevalence varies with age, race and education. According to some studies, 60% 80% of both men and women will develop hypertension by age of 80 [3]. Analysis of the global burden of hypertension revealed that over 26% of the world’s adult population had hypertension in 2000, and has shown a rapid increase in prevalence affecting signi icant numbers of individuals in Sub-Saharan Africa [4].


Introduction
An event involving drug therapy that actually or potentially interferes with the desired health outcomes is known as drug therapy problem [1]. Drug therpy problems is de ined by the World Health Organization (WHO) as "any response to a drug which is noxious and unintended and which occurs at doses normally used in man for prophylaxis, diagnosis or therapy of disease, or for the modi ication of physiological function" [2]. Hypertension is the most common cardiovascular disease. In a surveyed carried out in 2009, hypertension was in 28% of American adults and 60% of adults 65 years or older [1]. The prevalence varies with age, race and education. According to some studies, 60% -80% of both men and women will develop hypertension by age of 80 [3]. Analysis of the global burden of hypertension revealed that over 26% of the world's adult population had hypertension in 2000, and has shown a rapid increase in prevalence affecting signi icant numbers of individuals in Sub-Saharan Africa [4].
Studies worldwide indicate that despite the availability of effective medical therapy, more than half of hypertensive patients on treatment have blood pressures over 140/90 mm Hg threshold [5]. This is mostly because of drug therapy problems which include but not limited to non-compliance, ADRs, improper drug selection and drug interactions.
The occurrence of a DTP among hypertensive patients could prevent or delay patients from achieving desired therapeutic goals [6]. It has been attributed to unnecessary over-prescription of drugs, substantial worsening of diseases, avoidable increases in hospital admission rates, and longer hospital stays leading to a signi icant medical burden [7]. As a result, substantial numbers of patients do not get the maximum bene it of medical treatment, resulting in poor health outcomes, lower quality of life, increased health care costs and erodes public con idence in health systems [8].

Objective
This study aimed to assess the Knowledge, attitude and practice towards hypertension among hypertensive patients receiving care in a Nigerian hospital.

Eligibility criteria:
The eligibility criteria included all the folders of hypertensive with Diabetes comorbidity outpatients who received prescription from the hospital within the study period (August-September 2019).

Sample size calculation:
All folders that fell within the eligibility criteria were utilized for the study. A total of 171 patient folders were used.

Data collection
The data were collected from the patients' medical records using the Pharmaceutical Care Network Europe (PCNE) Classi ication tool Version 6.2 (PCNE, 2010). For each of the 171 medical records, the DTPs experienced within the study period were identi ied. The demographic information such as age and gender were recorded. Other items documented were the drugs implicated in the therapy problems, type of drug therapy problem, cause of drug therapy problem (DTP), type of intervention and the outcome of intervention. The PCNE V 6.2 has 4 primary domains for problems, 8 primary domains for causes and 5 primary domains for interventions. On a more detailed level, there are 9 grouped sub-domains for problems, 37 grouped sub-domains for causes and 17 grouped subdomains for interventions. The sub-domains are explanatory for the principal domains.

Data analysis
Data were analyzed using the IBM Statistical Product and Service Solutions (SPSS) for Windows, Version 21.0 (IBM Corp, Version 21.0, and Armonk, NY, USA).

Results
Majority of the patients were above 65years of age 64(37.4%), while about half of the patients were females. Also, most of the patients were traders 62(36.3%), 146(85.4%) were married, 146(79.1%) were Christians by religion and 164(95.9%) were currently non-smokers as at the time of the study (Table 1).
A total of 644 drug therapy problems were identi ied. Some of the drugs involved in DTP were, methyl dopa, frusemide, Nifedipine, lisinoril, metformin, metronidazole, analgesics like diclofenac, ibuprofen and paracetamol ( Table 2).
Majority of interventions made were on drug level 288(44.7%), while 183(28.4%) were made on patient level. Also, 152(23.6%) of the interventions were made on prescriber level while 21(3.3%) of the DTPs had no intervention ( Table 4).
Majority of the interventions made were accepted 586(91.0%) while only 3(0.5%) of the interventions made were not accepted (Table 5).

Discussion
Various drug combinations were responsible for the DTPs which may have resulted to therapy failure or adverse drug reactions. The use of methyldopa with frusemide constituted the major drug therapy problems in this study. Majority of the identi ied DTPs were due to adverse reactions. Most of the respondents were above 65 years of age, female and taking more than two medications. This is supported by the indings that adverse drug reactions occur mainly in young and middle aged adults and are twice as common in women [10]. From this study, patients who were on more than one medication experiences DTP more than those that were on a single medication. The use of multiple medications predisposes patients to adverse drug reactions [11]. Most of the patients in this study were on more than three drugs. Some of these medications may also predispose the patients to other disease states as a study showed that the long duration of therapy with beta-2 agonists positively correlated with the incidence of hypertension [12]. Our indings establish that prescribing error and inappropriate drug combinations were the major cause of drug therapy problems. This contrasts the results obtained in a recent study on drug therapy problems in adult hypertensive patients where about 40% of the drug therapy problems were due to non-adherence to medication (66%) [13]. Several studies have shown that most DTPs (48.75%) were from potential drug interactions [14]. Pharmacists can help in the making the right choice of drugs and possible combinations. Also, counselling can improve patient adherence and the outcome of therapy [14]. Inappropriate drug selection may be due to inappropriate prescribing. Less than a quarter of the DTPs had no documented interventions which might have stemmed from poor attitudes to documentation and poor patient-care approach. From the interventions documented, more than three-quarter had known intervention outcomes. Poor drug history documentation may lead to medication errors [15]. Health professionals should document appropriately to minimize or eliminate medication errors. Pharmacists' participation in medication history documentation might signi icantly increase the frequency and depth of medication history information documented [15].

Conclusion
This study demonstrates that a pharmacist, with adequate training and support can play a vital role in identifying and resolving drug therapy problems in the hospital. Also, there is a need for an educational intervention among prescribing physicians to always keep them abreast with the current hypertension guidelines.