Psychometric properties of the Pressure Ulcer Knowledge Test (PZ-PUKT) among nurses

Introduction

Pressure ulcers pose a significant medical and social problem despite the increasing number of studies focusing on their aetiology, pathogenesis, and methods of prevention and treatment. Evidence is still sought to determine the risk factors for the development and progression of pressure ulcers in various patient groups, as well as effective and cost-effective methods of prevention and treatment [1]. Implementing preventive measures effectively reduces the risk of developing deep pressure ulcers in many cases. However, despite guidelines and recommendations regarding care, the prevalence rate of pressure ulcers remains high in Europe and North America (7.6–26.0%). It is estimated that in the United States, pressure ulcers affect over 2.5 million patients receiving care [2]. Patients are at risk of developing pressure ulcers both in hospital and at home. According to Kottner et al. [3], the occurrence of pressure ulcers may affect over 70% of patients with self-care dysfunction. In Poland, nation­wide multicentre epidemiological studies have not been conducted to accurately indicate the coefficients and statistical data concerning the epidemio­logy and effectiveness of treatment. Regional single studies indicate similar results to those presented in Anglo-American literature. It is estimated that in hospital wards, this problem may affect between 3 and 17%, and in long-term care, between 17% and 28% [4]. Treating pressure ulcers after preventive measures becomes an equally serious problem in modern healthcare due to such high rates and the long period of time required for wound closure.
Pressure ulcers cause pain, discomfort, and reduced quality of life for patients, and they are associated with prolonged hospital stays and high healthcare costs. They can also pose a threat to the patient’s life [5, 6]. The priority in caring for patients at risk of pressure ulcers should be preventive measures, for which nurses are responsible [7]. A meta-analysis conducted by Dalvand et al. [8] indicates that nurses’ knowledge of pressure ulcer prevention is insufficient and often based on intuition and habit rather than evidence-based methods. Nurses’ knowledge and skills are recognised as factors shaping their positive attitudes towards wound prevention and treatment [8–12].
Considering the importance of knowledge about pressure ulcers, a reliable tool for its assessment is essential. Objective assessment of nurses’ knowledge should be used to design educational programs and plan training sessions [13–18]. So far, there has been no standardised tool available in Polish settings for assessing nurses’ knowledge of pressure ulcer prevention and treatment. Several tools for assessing knowledge about pressure ulcers are available in the literature, such as the Pressure Ulcer Knowledge Assessment Tool (PUKAT) developed by Beeckman et al. [18] or the Pressure Ulcer Knowledge Test (PZ-PUKT) developed by Barbara Pieper and Karen Zulkowski in 2014 and modified in 2021 [19]. The validity, reliability, and internal consistency of the PZ-PUKT have been verified and confirmed in various studies [20–22].

Aim of the research

Evaluation of the psychometric properties of the PZ-PUKT in a group of nurses.

Material and methods

Ethical considerations

The guidelines of the Helsinki Declaration were introduced during the conducted study. Participants were informed about the purpose of the study and provided informed consent before starting the study, and they could withdraw at any point without giving a reason [23]. Permission to conduct the cultural adaptation process and psychometric studies of the PZ-PUKT was obtained from the authors, Barbara Pieper of the College of Nursing at Wayne State University de Detroit, Michigan, and Karen Zulkowski of the College of Nursing at Montana State University, Bozeman, Montana, in the United States.

Course of the study

The study was conducted in 2 stages. In the first stage, the tool along with its description was translated into Polish by 2 independent translators. Subsequently, a 5-member expert panel consisting of 2 physicians and 3 nurses specialising in wound prevention and treatment was formed. The panel compared the translations and verified the consistency and correctness of the translation of individual questions. In assessing the correctness of the translation of questions, the guidelines of the Polish Wound Management Society (PTLR) [1] and the National Pressure Injury Advisory Panel (NPIAP) [3] registered in the United States were taken into account. Subsequently, cultural adaptations were made to better express certain items. No controversial or inconsistent content with the recom­mendations was noted in the prepared tool. The study was conducted with a group of 82 nurses during their specialised training, organised by the Postgraduate Nursing and Midwifery Education Centre (Polish OKPPiP) in Rzeszow, Poland. The following criteria were assumed for selecting the study group: a minimum of 1 year of professional expe­rience, competence in wound treatment, and interest in the issue and the studied area. Participants received instructions for completing the questionnaire along with the Polish version of the PZ-PUKT, and each person could withdraw from the study at any time. The time allocated for responses was 60 min, although the majority of participants completed the assessment within an average time not exceeding 20 min. Prior to the study, participants were asked to adhere to the rules applicable to examinations to ensure the reliability and validity of the results.

Research methods and tool

The method of estimation and a diagnostic survey was utilised in constructing the methodological assumptions. The research instrument consisted of a standardised test on pressure ulcers knowledge: the Pieper-Zulkowski PZ-PUKT, developed at the University of South Australia, 2021 version [19, 20]. Permission was obtained from the authors of the PZ-PUKT to prepare the Polish-language version. The tool comprises 72 items and assesses knowledge in 3 subscales: prevention (31 statements), stages of pressure ulcers (21 statements), and wound description (20 statements). Each item has 3 response options (true, false, and don’t know), and participants receive 1 point for each correct answer and 0 points for an incorrect answer. Out of the 72 statements regarding pressure ulcers, 42 statements are true, and 30 are identified as false. The total score of the test ranges from 0 to 72 points [19, 20].

Statistical analysis

Analysis was conducted using IBM SPSS Statistics v21. The Kolmogorov-Smirnov test was employed to assess the normality of distributions. Cronbach’s a coefficient was utilised to evaluate the reliability of the scale. Spearman’s r correlation coefficient was used to assess relationships between variables, and non-parametric tests for significance differences in distributions included the Mann-Whitney U test and the Kruskal-Wallis test.

Difficulty and discrimination indices

Two indices were also utilised to evaluate the quality of scale items: the difficulty index (DIFF) and the discrimination index (DISCR). The difficulty index for each item is calculated as the percentage of participants who answered the question correctly, i.e. the ratio of individuals who answered the question correctly to the total number of respondents. The discrimination index indicates the extent to which a given question differentiates individuals achieving high and low scores on the scale. To calculate the discrimination index from the study sample, the approach of Moharramzadeh et al. [20] was adopted. A subset comprising 27% of individuals with the highest scores on the scale and 27% with the lowest scores on the scale was extracted, and then the discrimination index was calculated as the difference in the percentage of correct answers between the 2 groups.
In Table 1, the difficulty and discrimination indices of the questions are presented. A difficulty coefficient below 0.30 is considered too difficult; above 0.70 is considered easy; and optimal values should fall within the range 0.30 to 0.70. Discrimination values below 0.10 indicate that the question is of low quality and should be discarded or subjected to detailed review; for values from 0.10 to 0.20, the question is reasonable but should be reconsidered; for values from 0.20 to 0.30, the question is moderately useful but may require minor revision [20, 24, 25].

Characteristics of the study participants

The study included 81 women (98.8%) and 1 (1.2%) man. The age of the participants ranged from 25 to 66 years, with an average age of 43.4 ±9.92 years. Most participants (77.2%) had completed higher education, including 46.4% at the master’s level and 32.8% at the bachelor’s level. According to Polish law, the entire study group had qualifications in pressure ulcer prevention and the independent selection of pressure ulcer treatment methods. The selection of the study group was purposive because the participating nurses were involved in the prevention and treatment of pressure ulcers in independent practice as well as in primary health care (Polish POZ). Detailed data on the education of the study group are shown in Table 2.

Results

The level of knowledge among the participants was assessed as above average, with the accuracy of responses in the test exceeding 60%. An evaluation of the test’s consistency was conducted, with Cronbach’s a for the entire tool reaching 0.726. In the 3 respective subscales of the questionnaire, the obtained values of the a coefficient were lower, reaching the following values: prevention 0.50, stage 0.47, and wound 0.38. The data are shown in Table 3.
Attention was drawn to the low a coefficient (0.383) in the wound subscale. Therefore, 2 indicators were used to assess the quality of the PZ-PUKT questions: the DIFF and the DISCR. The difficulty index for each question was calculated as the percentage of participants who answered the question correctly, i.e. the ratio of those who answered the question correctly to the number of all respondents. Three questions were identified that should be redesigned due to their low index (questions 12, 26, and 34). The average difficulty index for all participants was 0.67, and 26 questions (36.1%) had a good level of difficulty. However, excluding participants who chose the “don’t know” option, the average difficulty index only slightly increased to 0.68, with 27 questions (37.5%) achieving a good level of difficulty.
The average discrimination index was 0.21, with 19 questions (26.4%) achieving a good level. After excluding participants who chose the “don’t know” option, the average discrimination index decreased to 0.18, with 14 questions (19.4%) achieving a good level. In the entire set, there were 9 questions (12.5%) that simultaneously had a good level of difficulty and discrimination (DIFF = 0.30–0.70 and DISC ≥ 0.30). After excluding participants who chose the “don’t know” option, the number of questions decreased to 7 (9.7%). The data are shown in Table 4.

Discussion

In the conducted study, the psychometric properties of the Pressure Ulcer Knowledge Test (PZ-PUKT) were examined. It was confirmed that the level of knowledge among the participants was above average. The accuracy of the correct answers in the test exceeded 60%, although it was observed that the option “don’t know” was much less frequently chosen compared to other studies [20, 26]. The assessment of the overall test consistency (Cronbach’s a = 0.726) was at an acceptable level; however, a low consistency was observed in the 3 individual subscales. Two hypo­theses regarding the low consistency of the individual scales were assumed, related to incorrect question construction or inadequate knowledge in the specific area among the participants. To verify the hypotheses, qualitative indicators recommended in the validation study conducted by Moharramzadeh et al. [20] were used. The DIFF and DISCR are indicators illustrating the extent to which a given question diffe­rentiates between individuals achieving high and low scores on the scale. The conducted analysis unequivocally indicates that the question construction is correct and falls within the preferred ranges. Three questions were noted that need to be reconstructed, while the remaining questions forming the tool are at an acceptable level. A detailed analysis of the tool draws attention to the low-quality responses, especially in the domain of assessing wounds, which may indicate a lower level of knowledge among the participants regarding wound assessment. In the overall assessment of the tool, the obtained results are satisfactory and comparable to other studies evaluating the tool in Iran [20], the Philippines [22], China [26], and Brazil [27].
Observational studies over the past 2 decades have highlighted an increase in the incidence of pressure ulcers, with healthcare workers reporting difficulties in providing effective preventive and therapeutic measures, especially among older adults, chronically ill individuals, and those in terminal condition [2, 3, 17]. In the realm of healthcare provision, emphasis is placed on the adoption of “evidence-based practice” [28]. Both in Poland and globally, guidelines stress the importance of healthcare personnel’s knowledge level in pressure ulcer prevention and treatment. Utilising a globally accepted standardised tool would provide an opportunity for an objective assessment of healthcare personnel’s preparedness for pressure ulcer prevention and treatment, as well as to identify areas for reinforcement and development.
The process of cultural adaptation, validation, and examination of the psychometric properties of the Polish language version of the PZ-PUKT test offers an opportunity to fill an existing knowledge gap in this thematic area. This study serves as the basis for further in-depth multicentre research within the country and establishes a bridge with researchers from other countries for the exchange of experience [29].

Implications for practice

Nurses possess the competencies to implement comprehensive preventive and therapeutic interventions in the identification and treatment of pressure ulcers. Having knowledge resources in this area alongside practical skills is highly demanded. This study provided valuable insights into the strengths and weaknesses of the PZ-PUKT, as well as the level of knowledge in specific domains among the surveyed sample of nurses.

Limitations

This study utilised a specific and purposive sample of nurses engaged in independent practice as well as in primary health care (Polish POZ), and the obtained results of the knowledge level should not be generalised to other areas of nursing. The extensive range of questions comprising the PZ-PUKT may have influenced the accuracy in responding to the questions, and it can be assumed that during the time that the participants had to prepare for the questionnaire, the quality of responses may have deteriorated.

Conclusions

The PZ-PUKT questionnaire meets the basic standards regarding the consistency and quality of question construction, despite 3 questions requiring further refinement of the tool. Further research utilising this questionnaire is recommended, especially within the framework of higher education and specialised training courses. The obtained results should be evaluated and collected from academic centres to systema­tise and evaluate the knowledge domain for future recommendations in the prevention and treatment of pressure ulcers.

Funding

No external funding.

Ethical approval

Not applicable.

Conflict of interest

The authors declare no conflict of interest.

References