This study was undertaken under the aegis of the FH ‘Ten Countries Study’ which investigated several pertinent areas of FH care in the Asia-Pacific Region [25]. It was conducted in two parts. The first part involved adaptation and validation of the FH KAP questionnaire; and the second part was determination of the FH KAP among Malaysian PCP using the adapted and validated questionnaire. This paper presents the detailed methods and findings of the first part of the study. The second part of the study and its results was already published in 2018 [27]. The sampling for the first and second parts was mutually exclusive i.e. participants who were recruited in the first part of the study were excluded from the second part.
Study design and participants
This was a cross-sectional questionnaire validation study conducted in two phases. Phase 1 was the content validation, adaptation and face validation of the FH KAP questionnaire. Phase 2 was the field testing and psychometric evaluation.
This study was conducted between January 2016 and January 2017 among a group of PCP in Malaysia consisted of Medical Officers (MO), General Practitioners (GP) and Family Medicine Specialists (FMS). Those registered with Malaysian Medical Council and have one or more years of working experience in the Malaysian primary care settings were included. Those who were working as locum doctors in primary care clinics or those who were from medical specialties other than family medicine were excluded.
PCP with postgraduate qualification (PCP-PG-Qual) was defined as those who have completed formal PG training i.e. Diploma in Family Medicine (DFM), Master of Family Medicine, Fellow of the Royal Australian College of General Practitioners (FRACGP), and Member of the Royal College of General Practitioners, United Kingdom (MRCGP, UK). PCP without postgraduate qualification (PCP-noPG-Qual) was defined as those working in primary care with basic medical degree such as Bachelor of Medicine, and Bachelor of Surgery (MBBS) and Doctor of Medicine (MD).
In Phase 2, the psychometric evaluation involved construct validity and reliability testing. Construct validity was conducted by testing differences between two groups with expected differences to establish known-groups validity [28]. PCP-PG-Qual was hypothesized to have better KAP regarding FH compared to PCP-noPG-Qual. Reliability testing involved internal consistency analysis using Kuder Richardson formula–20 (KR–20) reliability coefficient [29]; and test-retest reliability using Cohen’s kappa statistics to measure the stability of the responses to the questionnaire over time [30]. Figure 1 outlines the two phases of the adaptation and validation processes.
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Study instrument
The FH KAP questionnaire used in this study was originally designed by Bell et al. [18]. Written permission to adapt and validate the questionnaire was obtained from the questionnaire developer via e-mail prior to the conduct of the study. The questionnaire was developed in the English language and consisted of 19 items divided into three domains i.e. knowledge, awareness and practice. The questionnaire items and responses were presented in various forms which included 7-point Likert scale, single best answer, multiple answer, ‘Yes/ No/ Don’t know’ and free text answer. Most of the questions have predetermined correct answers.
There were seven items in the knowledge domain covering the following areas: i) description of FH; ii) identification of lipid profile in FH; iii) prevalence of FH in Australia; iv) inheritance of FH in first-degree relatives; v) CAD risk in untreated FH; vi) age threshold for premature CAD; vii) role of genetic testing in FH. The awareness domain consisted of three items covering the following areas; i) familiarity with FH; ii) Australian clinical guideline on FH; iii) lipid specialist service. There were nine items in the practice domain covering the following areas; i) assistance in FH detection; ii) number of FH cases under care; iii) screening of relatives in FH cases; iv) family screening of FH among premature CAD; v) preference on effective healthcare provider in FH detection; vi) age for FH screening among young individuals in a family with premature CAD; vii) referral of FH patients to lipid specialist; viii) pharmacological agents used in hypercholesterolaemia; ix) combination of pharmacological agents used in severe hypercholesterolaemia.
Phase 1: Content validation, adaptation and face validation
Content validation and adaptation
The content validation involved seven experts, consisting of three FMS who were familiar with clinical care and management of FH, three chemical pathologists who run a lipid specialist clinic and one public health physician who had broad experience in questionnaire validation process. The panel of experts reviewed the original 19-item FH KAP questionnaire for conceptual and item equivalence. The panel reviewed the relevance of each questionnaire item and ascertained whether the contents were appropriate to the study objectives and the local context. The questionnaire was not translated into the Malay language because most doctors in Malaysia including PCP are proficient in English.
Conversion of the questionnaire into an online survey instrument
The adapted paper-based FH KAP questionnaire was then converted into an online survey questionnaire using the Google® Forms [31]. Relevant information about the study was given on the first page of the online survey and also in the email containing the link to the survey. The information given was the same as the paper-based information sheet, containing the identity of the researchers, contact details, the reason for conducting the survey and how the data would be used. The study information sheet also highlighted the right of the participants to anonymously and voluntarily participate in the study and the right to withdraw from the study at any time without any reason and without penalty. Informed consent was obtained via the online questionnaire when the respondent had to click the ‘Consent’ button before the next page of the questionnaire could be accessed.
The questionnaire was divided into three sections. Section A contained questions on the inclusion and exclusion criteria. Participants could only proceed to Section B and C, if they fulfil the eligibility criteria. Section B contained questions covering the KAP domains. Section C included questions on demographic characteristic, qualification and work experience. Participants could omit to answer any of the items as none of them required an obligatory response (other than those relating to the consent) before they could proceed until the end of the questionnaire.
Face validation
Face validation of the adapted FH KAP questionnaire was conducted among 10 PCP who fulfilled the inclusion and exclusion criteria, and who were naive to the study. The 10 PCP were given both the paper-based and online versions of the questionnaire. The questionnaire was self-administered, and participants were requested to take note of the time taken to answer the questionnaire, clarity of the content, language and wording used and the general structure of the questionnaire. Their opinions on understanding the instructions, contents, wording and general structure of the questionnaire were assessed and recorded. The result was discussed among the panel of experts. Minor correction and fine tuning of the questionnaire were addressed according to their comments and suggestions.
Phase 2: Field testing and psychometric evaluation
The adapted FH KAP online questionnaire was field tested amongst PCP who fulfilled the same inclusion criteria as in Phase 1. However, PCP who participated in Phase 1 and 2 were mutually exclusive, as those who participated in Phase 1 were not recruited for Phase 2.
Sample size
Two sample sizes were calculated for this study, one for the known-groups validity and the other for the reliability testing. The known-groups validity compared mean or median percentage score of FH KAP between PCP-PG-Qual and PCP-noPG-Qual. Therefore, the sample size for each group was calculated using the OpenEpi software for comparison of two means formula [32]. As there was no previous study comparing KAP between PCP-PG-Qual and PCP-noPG-Qual related to FH, the calculation was therefore made based on the previous study by Mosli et al., which compared KAP regarding colorectal cancer screening among two groups of PCP in Saudi Arabia [33]. Family Medicine trained physicians had higher mean knowledge score compared to physicians with MBBS only (4.93 ± 2.29 vs. 3.23 ± 1.88, P < 0.01) [33]. Based on the difference between the two means in this study, 95% Confidence Interval (2 sided), 80% power and a ratio of 1:1 between groups, the minimum sample size required for each group was 24 participants.
The sample size for the internal consistency reliability analysis using KR–20 was calculated based on the subject to item ratio for which a subject to item ratio of 5:1 was used [29]. Therefore, a minimum of 125 participants were needed (25 items×5 = 125). Considering estimated response rate of 10–30% for an online survey [34], the questionnaire was planned to be distributed to at least 1500 participants. Regarding test-retest reliability, sample size for testing the Cohen’s kappa agreement was determined to be 26, which was 20% of the total number of participants [35].
Sampling method
A link to access the adapted FH KAP online questionnaire was sent via email to 1500 PCP in the e-mail lists of two major professional bodies for PCP in Malaysia. The email contained information on the study background, purpose and benefits, participation in the study, study procedure, confidentiality as well as informed consent. They were invited to open a link to the online questionnaire.
The questionnaire consisted of three sections as previously described. Those who consented to the study and fulfilled the study inclusion and exclusion criteria in Section A were able to proceed to Section B and C of the online form. Once the questionnaire was completed and submitted, no modification was allowed. The participants had the right to withdraw from the study at any time without penalty. To avoid repeated response from the same participant, the questionnaire contained an item asking whether they have answered the questionnaire previously. For test-retest reliability testing, those who have responded were contacted via e-mail to obtain their second response after two weeks of their first response.
Questionnaire interpretation, coding and scoring
For item no. 1 which assessed FH familiarity, Likert scale scores of 1 to 4 were interpreted as ‘unfamiliar’ and coded as ’0’ while scores of 5 to 7 were interpreted as ‘familiar’ and coded as ’1’. The interpretation was done in accordance to the study by Rangarajan et al. [23] and Pang et al. [25]. For all of the items that have predetermined correct answers, incorrect response was coded as ’0’ while correct response was coded as ’1’. The questionnaire scoring was determined based on the study by Batais et al. [24] by summing up the correct responses of the items in each KAP domain. The possible minimum to maximum score for each participant ranged from 0 to 19 for knowledge, 0 to 13 for awareness, and 0 to 9 for practice domains. The maximum score for each domain was not similar with the number of items because some of the questions had multiple correct answers and thus, they were scored accordingly for each correct response. The actual score for each domain was then converted into percentage score for ease of comparison between the domains. Scores of 50% or more for each domain were considered acceptable [24, 25]. The scoring method of the adapted FH KAP questionnaire is described in Supplementary File 1.
Construct validation
The construct validity of the adapted FH KAP questionnaire was conducted using known-groups validation method in view of the dichotomous nature of the questionnaire responses rather than numerical or continuous form [28]. The questionnaire would be considered valid if it is able to significantly discriminate across groups of subjects that have been predicted or ‘known’ to differ from each other [28]. In this study, PCP-PG-Qual was hypothesized to have better KAP regarding FH compared to PCP-noPG-Qual. Therefore, the FH KAP questionnaire would be considered valid if it could significantly discriminate the mean or median FH KAP scores between the two groups.
Reliability testing
With regards to the internal consistency reliability testing of the adapted FH KAP questionnaire, KR–20 reliability coefficient which is a special form of Cronbach’s alpha was carried out in view of the dichotomous nature of the questionnaire’s responses [29]. KR–20 reliability coefficient of < 0.50 was interpreted as low, 0.50 - 0.80 was considered moderate and > 0.80 was interpreted as high [29].
For the test-retest reliability, 26 participants (20%) were requested to answer the questionnaire again after two weeks interval. Cohen’s kappa statistics, which is a robust statistical method, was used for the reliability testing because of the dichotomous nature of the questionnaire responses [30]. The kappa result was interpreted as follows: values ≤ 0 indicated no agreement, 0.01 - 0.20 as none to slight, 0.21 - 0.40 as fair, 0.41 - 0.60 as moderate, 0.61 - 0.80 as substantial, and 0.81 - 1.00 as almost perfect agreement [30].
Statistical analysis
Data were analysed using the SPSS software version 24.0 (SPSS Inc., Chicago, IL, USA). Missing data were treated using discrete value. Descriptive statistics were performed to depict the demographic background and practices information of the participants. Data were reported and presented as frequency and percentage. Before conducting the known-groups validity testing of FH KAP between PCP-PQ-Qual and PCP-noPG-Qual, normality of data distribution and equality of variance were examined. For the normally distributed data, independent t-test was applied to compare the mean percentage score of FH KAP between the 2 PCP groups, and for the non-normally distributed data, Mann Whitney u-test was applied. The statistically significance difference between the two groups was reported using P-value of < 0.05. For the internal consistency reliability testing, the KR–20 coefficient [36] for each KAP domain and the overall KR–20 coefficient were calculated. For the test-retest reliability testing using Cohen’s kappa statistics [30], the kappa value of each KAP item and the average kappa value were calculated.
Ethical considerations
The ethical approval for this study was obtained from the Research Ethics Committee (REC), Universiti Teknologi MARA (600-IRMI (5/1/6). The designing of the online survey questionnaire using the Google® Forms complied with the British Psychological Society Ethics Guidelines for Internet-Mediated Research, 2013 [37]. The study information provided on the first page of the questionnaire highlighted the right of the participants to withdraw from the study at any time without any reason and without penalty. Informed consent was obtained via the online questionnaire when the respondent had to click the ‘Consent’ button before the next page of the questionnaire could be accessed. Participants could omit to answer any of the items as there was no item (other than those relating to the consent) required an obligatory response before they could proceed until the end of the questionnaire. The survey was made anonymous by switching the option to collect computer IP addresses to ‘No’. To ensure confidentiality, the password to the Google® Forms account was only known to the researcher and data were not stored within a shared account.