1 Introduction

Hypertension is a global health concern [1], affecting a significant proportion of the global population, with the highest prevalence for mortality [2]. The prevalence of hypertension has significantly increased in Nigeria during the past 20 years, and despite increased awareness on hypertension among the general population, clinical treatment and control rates are still low [3]. According to the WHO (2020), hypertension affected 46% of adults aged 25 and above, with the American region having the lowest prevalence and the African region having the highest [4].

The European Society of Hypertension and the European Society of Cardiology guidelines endorsed home BP measurements which has been reported to give more reliable BP measurements, compared with BP measurements done in hospitals [5, 6]. Nevertheless, the home BP measurements must be properly done so as not to introduce errors. Although many printed detailed information is available on appropriate methods of BP measurements, quite a few patients yet commit errors while taking their BP at home [7, 8].

Inadequate patient training on BP measurement by healthcare professionals has been reported by many studies as a major reason for inaccurate BP measurement by patients [9,10,11]. Nessler and colleagues found out that only one-third of patients were counselled on appropriate BP techniques from a healthcare professional [12]. In the long run, data provided by patients on their home BP measurements could mislead physicians’ judgment on patients’ BP management and lead to wrong decision making.

Studies have shown that patients’ health outcomes improve when pharmacists get involved in patient counselling. A study reported that only fifty percent of patients with hypertension were counselled by pharmacists on the appropriate use of their BP monitoring device [13]. A tertiary hospital is a referral centre meant to address conditions that could not be successfully managed in primary and secondary healthcare centres. Also, tertiary hospitals in Nigeria undertake postgraduate residency training for healthcare practitioners, making the environment academic. There is therefore little or no margin for errors. It therefore becomes imperative that healthcare professionals, including pharmacists, be involved in patient counselling on BP measurement technique. This study therefore seeks to evaluate pharmacists’ knowledge and counselling on blood pressure measurement among pharmacists in a tertiary hospital.

2 Methods

2.1 Study design and setting

An interventional study was carried out among pharmacists at the University College Hospital (UCH), a tertiary healthcare facility in Ibadan, Nigeria. The UCH, a 950-bed hospital, was founded in 1957 and is the foremost Nigerian healthcare institution located in the busy metropolitan city of Ibadan. Pharmacists in the tertiary healthcare facility provide pharmaceutical services to patients in the hospital as well as satellite facilities within and outside the city, under the administration of the UCH.

2.2 Sample size determination

The sample size was determined using Raosoft sample size determination with a margin of error of 5% and a confidence level of 95%, and with an estimated population size of 180 pharmacists at the UCH. An extra 10% of the calculated sample size was added to make allowances for attrition, making a total 135 pharmacists.

2.3 Design and validation of data collection tool

The semi-structured questionnaire utilised as research tool for the study was designed based on the teaching and practice experience of the corresponding author, and sequel to extensive literature search by both authors [7, 10,11,12, 14,15,16,17,18,19,20,21,22]. Face validation was done by pretesting among 15 pharmacists at the University of Ibadan Health Services, Jaja, Ibadan to ascertain that the questions were not ambiguous. Content validation was done by five faculties at the Department of Clinical Pharmacy and Pharmacy Administration, Faculty of Pharmacy, University of Ibadan. The five faculties, comprising a Professor, an Associate Professor, two Senior Lecturers, and a Lecturer I, all had several years of experience on the practical aspect and didactic lectures in blood pressure measurement. They are well versed in intervention studies aimed at improving quality of care provided by pharmacists for patients. In addition, they have made extensive contributions in Clinical Pharmacy with several publications in both local and international peer-reviewed journals. Changes were made to the original questionnaire based on the face and content validation, such as adding a follow up question under Section B for the participants to explain their response to questions on the appropriate arm to be used for a patient’s first-time blood pressure measurement and the blood pressure reading to be recorded. Cronbach alpha coefficient calculated to check the internal consistency reliability for the 15-item knowledge assessment scale and 4-item counselling assessment scale were 0.82 and 6.73, respectively.

The 25-item questionnaire was divided into three sections. Section A addressed sociodemographic characteristics such as gender, years of practice and educational qualification. Sections B and C addressed knowledge and counselling on blood pressure measurement techniques, respectively. Section B comprised seven open-ended questions and eight close-ended questions. Four of the close-ended questions had yes or no responses, two three had options provided, and one was in a tabular form for the blood pressure classification. Section C had four open-ended questions. Pharmacists’ counselling ability was evaluated by asking them to state the stepwise procedure for blood pressure measurement with self-monitoring blood pressure device in counselling a patient. Also, they were asked to state the precautions that patients should observe during the measurement. They were also asked to state the recommended time of the day for measurement with reasons. Some of the items included arm to be used for BP measurement, BP reading to be recorded following multiple measurements, precautions for accurate BP measurement, and the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC VII) classification of BP.

2.4 Data collection procedure

The purpose of the study was explained to the pharmacists at the study site. The questionnaire was administered to consented pharmacists, who were consecutively sampled, at their respective units (comprising ward, outpatient, drug information and supply chain management sections) and retrieved immediately after completion. The pharmacists were reassessed with the same questionnaire one-month postintervention. The study period was from December 2022 to May 2023.

2.5 Intervention

An educational intervention was carried out by the corresponding author who had gone through relevant local and international trainings on blood pressure measurement. He is also a doctorate degree holder at the Department of Clinical Pharmacy and Pharmacy Administration, Faculty of Pharmacy, University of Ibadan, Nigeria, where he has had over ten years teaching experience as a faculty. The aim of the intervention was to address knowledge and counselling gaps on BP measurement observed among the pharmacists. The intervention comprised didactic lectures, case studies, demonstrations, interactive, question and answer sessions on knowledge and counselling on BP measurement, using both manual and automatic BP monitoring devices. The training, which took place at the seminar room at Pharmacy Department of the University College Hospital, Ibadan, lasted for about an hour.

2.6 Data analysis

Data was analysed using IBM-SPSS for Windows, Version 20. Descriptive statistics such as frequency counts, percentages, median, and mean ± standard deviation were used to summarize data. The data was not normally distributed; therefore, non-parametric inferential statistical analysis was carried out. Inferential statistics was carried out as follows: Mann–Whitney U test for comparing knowledge and counselling assessment scores with educational qualification, and gender; Kruskal–Wallis test for comparing knowledge and counselling assessment scores with work experience; Wilcoxon signed rank test for comparing knowledge and counselling assessment scores pre and postintervention. Each correct response to the questionnaire was assigned “1” score, while each incorrect response was assigned “0” score. Under the knowledge section, the question on five precautions for manual BP measurement had five correct answers and the one on the JNC VII BP classification had a total of eight marks allocated to it. The remaining 12 questions were allocated a point each, and the total obtainable score was 26 marks. The counselling section was similarly scored; while the question on the stepwise procedure for use of self-monitoring BP monitors had six correct responses, the precautions for its use had five correct responses. The remaining two questions had a point each, and the total obtainable score for counselling on BP measurement was 13 marks.

2.7 Ethics approval

Ethical clearance for research was obtained from the joint UI/UCH Ethics Review Committee with approval number UI/EC/22/0066.

3 Results

One hundred and forty-seven pharmacists participated in the preintervention phase of the study, but 144 pharmacists completed the study. The three dropouts were on leave at the postintervention phase of the study. Gender distribution of the pharmacists was even with 75 (52.1%) being females. Ninety-three (64.6%) pharmacists had 1–5 years of work experience, 25 (17.4%) 6–10 years, and 26 (18.0%) greater than 10 years. Average years of practice was 5.13 ± 5.63 years.

There was an improvement in the knowledge assessment scores of the study participants on blood pressure measurements postintervention. Median scores of pharmacists’ knowledge on BP measurement improved significantly from 13.00 preintervention to 25.00 postintervention (p < 0.001). While majority of the study participants had “fair” knowledge preintervention, majority had “excellent” score postintervention. Before the educational intervention, only 62 (43.1%) pharmacists knew that blood pressure measurement had to be carried out in both arms for a first-time patient. Also, when asked the question “What BP reading will be recorded for a patient whose BP readings when taken thrice were 149/82 mmHg, 141/78 mmHg, and 139/78 mmHg?” only 38 (26.4%) provided the right answer. Similarly, majority of the pharmacists (51, 35.4%) could only state one out of five precautions during blood pressure measurement. Table 1 shows detailed information on the results from the knowledge assessment of the pharmacists on blood pressure measurements.

Table 1 Pharmacists’ knowledge assessment on manual blood pressure measurement
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The comparison of pharmacists’ counselling showed a significant improvement in the median scores from 1.00 preintervention to 12.00 postintervention (p < 0.001). Table 2 shows pharmacists’ assessment of counselling on self-monitoring blood pressure measurements while Fig. 1 shows the pre and postintervention stepwise counselling on the use of self-monitoring BP monitoring device. Relationships between pharmacists’ knowledge and counselling assessment, and variables such as gender, educational qualification and work experience are as shown in Table 3.

Table 2 Pharmacists’ counselling assessment on self-monitoring blood pressure measurement
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Fig. 1
figure 1

Stepwise procedure assessment of blood pressure measurement counseling

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Table 3 Comparison of pharmacists’ knowledge and counselling with gender, education, and work experience
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4 Discussion

Blood pressure (BP) measurement is an imperative routine hospital assessment utilized for diagnosis and monitoring of hypertension [21]. The need for accurate BP measurement for clinical decision making has been emphasized by clinical guidelines [23]. Regular use of self-monitoring BP (SMBP) device by patients is now encouraged to give a better picture of their BP monitoring progression for improved management by physicians [24]. Cremers and colleagues emphasized the vantage position occupied by hospital pharmacists to counsel patients on appropriate SMBP measurement [25]. Studies have proven that patient counselling by pharmacists, as part of their clinical care practice, leads to improved patient outcomes [26, 27].

The current study observed an improvement in the pharmacists’ knowledge and counselling on BP measurement sequel to the educational intervention. Previous intervention studies on medication reconciliation [28], ophthalmic preparations [29], and inhaled asthma medication devices [30] carried out in the same study population all reported similar results, postintervention. This underscores the need for continuous education for hospital pharmacists, especially on patient-focused clinical care activities to improve the quality of service delivered.

In this study, neither work experience nor additional qualification significantly influenced the pharmacists’ knowledge and counselling on BP measurement, before the intervention. This contrasts with the study conducted in the same study setting on inhaled asthma medication device [30]. The fact that pharmacists in the study setting do not engage in hands-on BP measurement for patients who access care at the healthcare facility may explain how work experience did not influence their preintervention knowledge and counselling on BP measurements. However, they are involved in counselling patients on asthma inhalation medication devices, which might afford them the opportunity to learn on the job and get to improve with increase in years of work experience. The poor pre-intervention results suggest that it may be necessary to recommend that schools of pharmacy include teaching on this topic in their undergraduate curricula This also calls for curriculum review for postgraduate studies to factor courses aimed at updating pharmacists on patient-oriented clinical care services.

Only one quarter of the pharmacists correctly answered the question, "What blood pressure reading will be recorded for a patient whose BP readings when taken thrice were 149/82 mmHg, 141/78 mmHg, and 139/78 mmHg?" before the intervention. The AHA American Heart Association recommends that only readings within 5 mmHg difference should be averaged [14]. Also, more than one-half of the pharmacists, preintervention, did not know that BP measurements should be carried out on both arms for first timers. According to the American Heart Association, the arm with the higher of the two should be recorded, and that subsequent readings should be done on the arm with the higher reading [14]. However, majority of the pharmacists were aware that someone whose BP was 145/94 mmHg on a routine screening and with no prior diagnosis of hypertension could not be said to be hypertensive. Such a person should be asked to engage in lifestyle modifications and asked to recheck his BP in one or two weeks later, and subsequently referred to a physician for a more comprehensive checkup.

Majority of the pharmacists could not state more than two precautions for accurate blood pressure measurements before the intervention. An earlier study by stated more than five precautions to take while taking blood pressure measurements [18]. Pharmacists counsel patients on precautions for appropriate blood pressure measurements. Although, a significant improvement was seen postintervention, it is important to evaluate quality of clinical care services offered by pharmacists to ascertain whether there is need for intervention or not. Only 15.3% of the pharmacists knew the recommended time for patients to take blood pressure readings during the preintervention phase of the study. According to the European Society of Hypertension guidelines [15] and the American Heart Association [18], it is recommended that patients take their readings in the morning before taking their medication (not immediately after waking up) and in the evening before dinner.

The absence of a control group to ascertain that the improvement observed in the study was on account of the intervention is a limitation to the study. The result of this study is neither generalisable to pharmacists in other tertiary healthcare facilities in Nigeria nor to those in community pharmacies.

5 Conclusions

Baseline knowledge and counselling of the pharmacists on blood pressure measurement was poor. The educational intervention significantly improved the pharmacists’ knowledge and counselling on blood pressure measurement.