Comparative study of knowledge, attitude, and practices of adverse drug reaction reporting among healthcare workers in primary and secondary health facilities

Study design

A comparative cross-sectional study was conducted among HCWs, including doctors, nurses, pharmacists, pharmacy technicians, and community health workers (CHWs) in primary and secondary healthcare facilities (SHCs) in Lagos, South-West, Nigeria. A comparison between primary and SHCs was essential to assess potential differences in pharmacovigilance knowledge, attitudes, and practices across varying levels of healthcare delivery and professional exposure. A validated self-administered questionnaire developed using methods from a previous study was utilized to collect data on HCWs’ knowledge, attitude, and practice regarding ADR reporting.^[17,18]

Inclusion criteria

The respondents were included full-time HCWs involved in the day-to-day care (clinical services such as patient assessment, diagnosis, treatment, and follow-up within the healthcare facility), as well as those engaged in prescribing, dispensing, or administering medications.

Exclusion criteria

The exclusion criteria were HCWs undergoing internships or industrial attachments, and those solely employed for administrative duties.

Study area

The study was conducted in Lagos State, Nigeria. Lagos is a cosmopolitan city with a diverse population and a mix of public and private healthcare facilities. The city is divided into several administrative divisions: Ikeja, Lagos, Ikorodu, Epe, and Badagry, including 20 local government areas and 37 local council development areas, with 26 registered general hospitals and over 325 primary healthcare centers (PHCs) in Lagos state. Lagos has a large healthcare workforce, including doctors, nurses, pharmacists, and other allied healthcare professionals. The city also has a well-established regulatory framework for pharmacovigilance and ADR reporting. The National Pharmacovigilance Center serves as the central coordinating body for ADR monitoring and reporting in Nigeria.

Sample size determination

The sample size was determined using the following equation: ^[7]

Where:

n = minimum sample size in each group

Zα = standard normal deviate at α probability, where α is 95% confidence interval

Zβ = standard normal deviation at β probability, where β = 1-power. Power is the probability of finding a significant result, and it was 80% that was used in this study

p1 = proportion of good knowledge of ADR reporting in primary healthcare facility in Ibadan 61.6%^[11]

q1 = complementary probability of p1, which is 1-p1

p2 = proportion of good knowledge of ADR reporting in the SHCs in Ekiti 42.5%^[11]

q2 = complementary probability of p2, which is 1-p2

d = effect size = p1-p2.

An estimated sample size of 104.9, with a 10% attrition rate, making 115.4. This was then rounded up to 150 to give room for robust coverage. This number was doubled to account for the design effect, and the final sample size used was 300 participants in all (150 PHCs and 150 for SHCs).

Sampling technique

A multistage sampling method was used to select the study participants from secondary and tertiary healthcare institutions. This method was chosen to ensure that the sample was representative of HCWs across different levels of care while accounting for the large number and wide distribution of facilities in Lagos State. Four SHCs and eight PHCs were selected, and proportionate sampling of HCWs from each healthcare facility was done.

Pre-testing and data management

The questionnaire was pre-tested among 10% of the HCWs sample size at random, and the results obtained were used to adjust the questionnaire for validity and reliability. Respondents were assigned unique identification numbers. The Statistical Package for the Social Sciences (SPSS) version 23 was used for data collation and validation for accuracy and completeness.

Study instrument

The questionnaire, drafted in English, comprised four sections (sociodemographic data, knowledge of ADR reporting, attitude toward reporting, and ADR reporting practices). In the knowledge domains, the maximum score was 10, and the correct answer was allocated 1 point, whereas the wrong answer was scored 0. The total score was converted into a percentage. A total score of ≥50% was classified as “Good” knowledge of ADRs and reporting, whereas a total score of <50% was classified as “Poor” knowledge.^[17] The questions in the attitude domain are 5-point Likert scale structured, and questions 1–5 are positive statements. Questions 6–8 are negative statements and were reversed for scoring. The maximum score was 45, and the total score of each participant was converted to a percentage. A total score of ≥60% was classified as a “positive” attitude toward ADR reporting, whereas a score of <60% was classified as a “negative” attitude.^[17]

Data analysis

The data collected were analyzed using SPSS version 23. The Chi-square analysis was used to identify the factors associated with knowledge, attitude, and practice. p ≤ 0.05 was accepted as being statistically significant.

Ethical considerations

Ethical approval was obtained from the Health Research and Ethics Committee (HREC) of the Lagos University Teaching Hospital, Lagos (ADM/DCST/HREC/APP/5877). Permission was also sought from the directors and heads of departments, and voluntary written informed consent was obtained from the participant that their participation in the study would not cause any harm. Before this, the interviewer explained the purpose of the study, risks, and benefits of participation. Participants were reassured that the information obtained was solely for research purposes and was kept confidential. Participants were permitted to withdraw from participation at any time without penalty or consequences. Privacy was ensured during interviews. No incentive was given for participation.

Sociodemographic characteristics

The age range with the greatest number of respondents in primary health care facilities was 30–39 years (34.7%), whereas in secondary health care facilities it was 40–49 years (34.7%). Female PHCs respondents account for 62.7% of the total populace, whereas 71.3% of SHCs respondents are female [Table 1].

A larger proportion of the respondents in PHCs had practiced for 0–5 years, whereas those from the SHCs had practiced for 6–10 years. The most recorded respondents’ profession in PHCs is CHWs (22.7%), whereas that of the SHCs is medical doctors (28.7%). This observation is statistically significant. Most of the respondents from both the PHCs and SHCs hold professional degrees other than the ones highlighted in the study. Majority of the respondents from both the PHCs and SHCs belong to the Yoruba tribe, and no significant difference was found between the age, gender, and year of practice. Most of the respondents in both primary and SHCs are married (64% and 77.3%, respectively).

Knowledge of pharmacovigilance

The knowledge of respondents in both primary and SHCs was high. There is a significant difference in the awareness and understanding of pharmacovigilance between PHCs and SHCs (a larger proportion of those in secondary healthcare centers have better knowledge), as depicted in Table 2.

There was a statistically significant difference in the knowledge of pharmacovigilance, as a higher proportion (90.7%) of respondents in SHC had good knowledge compared to 75.3% of those surveyed in PHCs [Table 3].

Respondents in PHCs between the ages of 40 and 49 have 91.5% good knowledge, whereas in the SHCs, 31–39 have 93.3% good knowledge. Males in PHCs (76.8%) and SHCs (88.4%) have good knowledge of ADRs. The females in SHCs have a better understanding than those in primary (91.6% vs. 74.5%). In both PHCs and SHCs, most of the medical doctors had better knowledge than other professions. Age, profession, and ethnicity were found to be statistically significantly associated with knowledge of adverse drug reporting [Table 4].

Attitude of the respondents toward ADR reporting

About 91.3% of those in PHCs have a positive attitude, and 98.7% of those in SHCs have a positive attitude [Table 5]. When asked if ADR reporting is a professional obligation for HCWs, about 95.3% versus 96.7% of those in PHCs and SHCs, respectively, agreed and strongly agreed that it was [Table 6]. This indicates a positive attitude toward ADR reporting monthly HCWs in both settings.

Respondents in PHCs between ages 40 and 49 years have 89.4% good attitude, whereas in the SHCs, 82.2% aged 30–39 years have a good attitude [Table 7]. A higher proportion of females in PHCs (91.5%) demonstrated a better attitude, whereas in SHCs, a greater proportion of males exhibited a positive attitude. More females in PHCs have 91.5% have better attitude, whereas more males in SHCs have a positive attitude. More of the nurses in PHCs have a better attitude toward ADR reporting, whereas more medical doctors in the SHCs have a better attitude. Gender and profession were found to be statistically significantly associated with knowledge of ADR reporting.

Practice of ADR reporting

Regarding practice, 81.3% of those surveyed in primary healthcare centers had patients who experienced an ADR, compared to 92% in SHFs [Table 8].

Knowledge of pharmacovigilance

The knowledge of ADR reporting varied across demographic groups. Among PHC respondents, those aged 40–49 demonstrated the highest level of good knowledge (91.5%), whereas in SHCs, the 31–39 age group showed the highest knowledge (93.3%), possibly reflecting differences in professional experience, career stage, and access to training opportunities. Male respondents in both PHCs (76.8%) and SHCs (88.4%) exhibited good knowledge. However, female respondents in SHCs had higher knowledge compared to their counterparts in PHCs (91.6% vs. 74.5%), which may be linked to greater representation of women in certain professions and better exposure to pharmacovigilance activities at secondary-level facilities. Across both healthcare levels, medical doctors consistently demonstrated better knowledge than other professional groups, likely due to broader pharmacology training and closer interaction with drug safety practices. These findings highlight the need for targeted, group-specific interventions to bridge gaps, ensuring equitable pharmacovigilance capacity across all HCW categories and facility levels.

About 42.7% and 76% of those in primary and secondary healthcare, respectively, were able to correctly define pharmacovigilance (P < 0.001), which is a similar finding to 62.3% reported in Jos, Nigeria.^[19] These data indicate a significant difference in awareness and understanding of pharmacovigilance, including NAFDAC’s activities, between PHCs and SHCs, with a higher proportion of HCWs in SHCs being more knowledgeable. This difference might be due to varying levels of training, resources, and exposure to pharmacovigilance practices in these two types of healthcare settings.

More respondents in SHCs understood better that the most crucial purpose of pharmacovigilance was to determine the drug’s safety when compared to those in PHCs (69.3% as compared to 62%). A greater percentage of respondents in SHCs appear to understand that the main objective of ADR reporting is to ensure the safety of medications. This shows that services offered in SHCs are more specialized, and this can be attributed to the conceivably greater exposure to pharmacovigilance practices and training.

A significantly larger proportion of respondents in SHCs (90%) were also more aware that Nigeria has a National Pharmacovigilance Program than those in the PHCs (74%). This is unlike in Ekiti, where there was a lack of awareness about the existence of a National Pharmacovigilance Centre in Nigeria, which is responsible for monitoring and reporting ADRs.^[20] This difference in awareness might be due to factors such as the level of exposure to national healthcare initiatives, the dissemination of information, or the emphasis on pharmacovigilance in secondary healthcare settings.

About 76.7% of those in primary healthcare facilities knew that the regulatory body responsible for monitoring ADRs is the NAFDAC, compared to 56.7% of those in SHCs. This difference in level of awareness could be due to various factors, which may include the level of education and training provided in these healthcare settings or differences in the emphasis placed on pharmacovigilance and regulatory matters in each of the settings.

The knowledge of the location of the International Centre for ADR monitoring averages in both primary and SHCs. This shows that there is no significant difference in the knowledge of the location of the International Centre for ADR monitoring between the PHCs and SHCs. About 53.3% in PHCs and 69.3% in SHCs knew the location of the International Centre for ADR Monitoring is in Sweden. This finding is also similar to the findings about the knowledge of the existence of the international regulatory body for ADR reporting. This can be attributed to the center’s operations and its prominence in global pharmacovigilance initiatives. Awareness of the International Centre for ADR reporting reinforces the global significance of local reports, motivating HCWs to participate more actively and consistently, as their contributions are recognized as vital to worldwide drug safety surveillance.^[21]

When asked about the healthcare professionals responsible for reporting ADRs in a hospital, a higher percentage of the respondents in SHCs (90.7%) had a better understanding than their counterparts in the PHCs (78.7%) healthcare facilities. This difference in understanding can be attributed to differences in the healthcare infrastructure, roles, and responsibilities, as well as the varying levels of emphasis on pharmacovigilance and reporting practices in these two healthcare settings. About 70.7% and 38% of respondents in SHCs and PHCs, respectively, correctly identified the clinical trial phase during which a rare ADR is most likely to be detected. Although understanding the clinical trial phase in which rare ADRs are typically identified is essential for healthcare professionals, this knowledge was found to be higher among respondents in SHCs compared to those in PHCs. This difference in knowledge underscores the importance of targeted education and training programs for healthcare professionals, particularly those in primary healthcare settings, to ensure they are well-informed about the various aspects of pharmacovigilance, including the identification of rare ADRs during clinical trials. This can contribute to better patient safety and the overall effectiveness of drug monitoring and reporting processes.^[22]

When asked about what marks up a serious adverse event, 44% and 30.7% respondents in the PHCs, whereas 41.3% and 37.3% of respondents in the SHCs responded correctly. This average knowledge about the identification of serious ADR events shows that, in both PHCs and SHCs, there is a need for intense training on pharmacovigilance. More respondents in the SHCs (87.3%) answered correctly that all ADRs should be reported. This is higher than their counterparts (66.7%) in PHCs. This indicates yet again that more healthcare professionals in the SHCs better recognize the need for reporting ADRs. A higher percentage of respondents (68% and 76% PHCs and SHCs, respectively) know that ADR reporting helps improve patient health outcomes.

Better knowledge and practice among all cadres of HCWs will ensure earlier detection of drug safety issues, reducing preventable morbidity and mortality. Furthermore, strengthening the pharmacovigilance activities at the PHCs will lead to an improvement in patient trust in the healthcare system and generate more comprehensive national safety data, which informs regulatory action and enhances public health outcomes. Ensuring NAFDAC’s compliance with international standards (including the creation of awareness in the general populace) will further promote the knowledge of pharmacovigilance and its need for reporting in the health care sector.^[23]

Attitude of the respondents toward ADR reporting

The great positive disposition of respondents in both PHCs and SHCs toward ADR reporting may be attributed to their ability to recognize its relevance to patient safety, which likely drives their willingness to report ADRs. Nevertheless, across individual attitude questions, there are varying degrees of attitude toward ADR. This is further corroborated by the great belief in respondents that ADR reporting is a professional obligation for HCWs in both PHCs and SHCs. When asked if ADR reporting is necessary for HCWs, 82.4% of those in PHCs agreed that it was necessary, and 90% of those in SHCs also agreed. 86% of respondents in PHCs agree and strongly agree that the drug reaction reporting committee should be mandatory in all healthcare facilities. Similarly, 96% of those in SHCs agree to the establishment of ADR committees in their facilities. Across both healthcare centers, there was a high level of agreement that healthcare professionals should be trained in-depth about pharmacovigilance, about 46% in PHCs and 84% in SHCs. This is in harmony with the attitude of healthcare professionals toward ADR reporting, as reported by a previous study in Ekiti state,^[20] which was generally positive. Since the results show a higher level of positivity and willingness to report ADRs among HCWs in both PHCs and SHCs, it is evident that HCWs generally hold a favorable attitude toward pharmacovigilance. This positive disposition presents an opportunity to strengthen ADR reporting systems by providing the necessary training, resources, and supportive infrastructure. Encouraging and sustaining this willingness can lead to more consistent reporting, which in turn enhances early detection of drug safety issues, improves patient outcomes, and supports regulatory bodies (NAFDAC) in making evidence-based decisions for safer and more effective medical treatments.^[24]

When questioned on whether pharmacovigilance committees ought to be made available in healthcare facilities, more of the respondents from PHCs (42%) and SHCs (48%) were undecided. The high proportion of respondents who were undecided about the need for pharmacovigilance committees in both PHCs and SHCs may reflect limited awareness of the role and function of such committees within healthcare systems. Strengthening awareness and establishment of pharmacovigilance committees within healthcare facilities could provide clearer reporting pathways, enhance accountability, and ultimately improve patient safety through more systematic ADR monitoring.^[25]

When asked if ADR has the potential to damage their professional image, more of the respondents in both PHCs (35.3%) and SHCs (42.7%) disagreed. 37.3% of respondents in PHCs and 44.7% in SHCs disagree that only patients benefit from ADR reporting. Most of the respondents in the PHCs (73%) and SHCs (53.3%) disagree on the idea that tolerable mild ADRs should not be reported. These findings indicate a poor perception toward the importance of pharmacovigilance, which may continue to influence the practice of pharmacovigilance eventually if not addressed. This observation was also reported by Akarowhe, 2020, who highlighted that many healthcare professionals and stakeholders show limited initiative in reporting ADRs.^[26] Unless initiatives are made to promote a positive attitude toward ADR reporting in Nigeria, the safety and efficacy of drugs will remain compromised.

Practice of ADR reporting

The data recorded for reporting of ADRs revealed that majority of the respondents in both PHCs and SHCs have observed ADRs in their patients. About 51.3% of the respondents in PHCs have never reported an adverse event to the pharmacovigilance center, whereas majority of the respondents in SHCs (64.7%) have reported. The higher ADR reporting in SHCs compared to PHCs may partly reflect the fact that more complex treatments and higher-risk medications are often administered in secondary facilities, leading to greater exposure to potential ADRs. It may also indicate structural and process-related differences between the two levels of care, such as better reporting infrastructure, greater interaction with regulatory bodies, or more frequent training opportunities in secondary care. For patients, this discrepancy suggests that those in primary care settings may be at greater risk of undetected or unreported ADRs, potentially compromising safety. Addressing these gaps by strengthening pharmacovigilance processes in primary healthcare facilities is therefore critical to ensuring equitable patient protection across all levels of care.^[23]

When asked if they report adverse events when they occur, over half (54%) of the respondents in PHCs responded that they sometimes report, whereas the SHCs (58.7%) report adverse events. When asked the reasons for failing to report ADRs, 31.3% of those in PHCs highlight that the reasons they have failed to report ADRs are due to insufficient time to report, whereas 35.3% in SHCs report that the reporting forms were unavailable. This finding is in line with that of a previous study, which found that of the 384 healthcare professionals surveyed in Ekiti, 18.8% of participants had ever reported an ADR, and only 6.8% had reported an ADR in the past year.^[20] Majority of the respondents in the PHCs (63.3%) and the SHCs (71.3%) have seen the ADR reporting forms. However, majority of the respondents from both the PHCs (34.7%) and SHCs (55.3%) have never received training on how to report an ADR. The lack of prior training on ADR reporting among most respondents in both PHCs and SHCs highlights a critical gap in pharmacovigilance capacity. Without such training, HCWs may be unable to recognize or report ADRs effectively, increasing the risk of underreporting and compromising patient safety. Addressing this gap through structured training and continuous medical education is essential to strengthen reporting practices and improve drug safety monitoring.

For the practice on what is done when an ADR is detected, about half (50.7%) of the respondents in the PHCs treat the ADR and report to the pharmacovigilance center. 59.3% of the respondents in SHCs also do the same. Majority of the respondents from both PHCs (68.7%) and SHCs (84%) report all kinds of ADR. This observation is significant. More than half of the respondents from both the PHCs (61.3%) and SHCs (56.7%) report that they prefer the Email/web format of reporting ADRs. These findings show that there is a low practice of pharmacovigilance in both PHCs and SHCs settings. This suggests that there are challenges or barriers to effective pharmacovigilance in these facilities that need to be addressed, and these challenges should commence with addressing the attitude of HCWs toward pharmacovigilance.

The study’s outcomes demonstrated awareness of ADR reporting and recognized it as a shared professional responsibility, reflecting a generally positive inclination toward pharmacovigilance. However, this attitude was not consistently matched by adequate knowledge or reporting practice, as gaps in training and awareness of reporting pathways remain evident. These discrepancies indicate that while the foundation for effective pharmacovigilance exists, it requires targeted interventions such as structured training, establishment of ADR committees, and stronger institutional support to ensure consistent reporting. Strengthening these areas will be essential to translate positive attitudes into improved patient safety outcomes. Positive attitudes toward ADR reporting among HCWs in Lagos provide a strong foundation, but without improved training, reporting structures, and institutional support, these attitudes cannot be fully translated into effective pharmacovigilance and patient safety.^[23]

Future directions

Future research should move beyond cross-sectional assessments and adopt longitudinal and nationwide study designs to capture changes in ADR reporting knowledge, attitudes, and practices over time and across diverse healthcare settings. Such studies would provide a more comprehensive understanding of regional variations, contextual challenges, and systemic barriers that influence pharmacovigilance in Nigeria. In addition, evaluating the long-term impact of targeted interventions such as structured training programs, integration of ADR reporting modules into medical and nursing curricula, and the establishment of pharmacovigilance committees will be essential for determining their effectiveness and sustainability. These insights will not only inform evidence-based policies to strengthen ADR reporting systems but also ensure that pharmacovigilance contributes more effectively to safeguarding patient safety and improving therapeutic outcomes nationwide.

Limitations of study

This study was limited by its cross-sectional design, which captures knowledge, attitudes, and practices at a single point in time and may not reflect changes over the duration of the study. Self-reported responses may also be subject to recall or social desirability bias, potentially over or underestimating knowledge and positive attitudes toward ADR reporting. In addition, the study was conducted in selected healthcare facilities in Lagos, which may limit the generalizability of the findings to other regions in Nigeria.