Siew Pheng Chan

Publications (3)5.86 Total impact

• Article: The effect of mandatory generic substitution on the safety of alendronate and patients' adherence.

  Pauline Siew Mei Lai, Siew Siang Chua, Yah Huei Chong, Siew Pheng Chan
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  ABSTRACT: Generic medicines are often used in public hospitals. However, data on the quality of generic alendronate, its efficacy, side-effects and medication adherence in clinical practice is scarce. Therefore, this study aimed to compare the side-effects and medication adherence of generic (apo-alendronate*) and proprietary alendronate (Fosamax†). This prospective study involved two groups of patients: (1) postmenopausal osteoporotic women prescribed once-weekly Fosamax (proprietary group) but were switched to apo-alendronate after 2 years ('switched over' group); and (2) patients initiated with once-weekly apo-alendronate (generic group). Participants were recruited from the Osteoporosis Clinic of a tertiary hospital. Data were collected through interviews. Side-effects and medication adherence. A total of 131 participants were recruited: proprietary group = 64 and generic group = 67. An intergroup and a within-group comparison were made. Side-effects were reported by 6 (9.4%), 30 (44.8%) and 12 (18.8%) participants in the proprietary, generic and 'switched over' groups, respectively. Participants who were on generic alendronate were at a significantly higher risk of experiencing side-effects compared to those who were taking proprietary alendronate [odds ratio (OR):7.84 (95% CI: 2.98-20.65), p < 0.001]. However, no significant statistical difference was found between the 'switched over' and the proprietary group [OR: 2.23 (95% CI: 0.78-6.37), p = 0.127]. Four out of 12 (33.3%) patients who experienced side-effects immediately after switching to generic alendronate discontinued generic alendronate due to intolerable gastrointestinal side-effects. There was no difference in medication adherence to generic or proprietary alendronate. Medication adherence to both generic and proprietary alendronate appeared similar although patients who were taking generic alendronate* were significantly more likely to experience side-effects than those on proprietary alendronate. Therefore, the switch from proprietary alendronate to the generic forms should not only consider the cost of the products but must also ensure that the generic and proprietary alendronate are equivalent in all aspects of efficacy and safety.
  Current Medical Research and Opinion 07/2012; 28(8):1347-55. · 2.38 Impact Factor
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  Available from: Chua Siew Siang

  Article: Validation of the diabetes, hypertension and hyperlipidemia (DHL) knowledge instrument in Malaysia.

  Pauline S M Lai, Siew Siang Chua, Ching Hooi Tan, Siew Pheng Chan
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  ABSTRACT: Patient's knowledge on diabetes, hypertension and hyperlipidaemia and its medications can be used as one of the outcome measures to assess the effectiveness of educational intervention. To date, no such instrument has been validated in Malaysia. Therefore, the aim of this study was to evaluate the validity and reliability of the Diabetes, Hypertension and Hyperlipidemia (DHL) knowledge instrument for assessing the knowledge of patients with type 2 diabetes in Malaysia. A 28-item instrument which comprised of 5 domains: diabetes, hypertension, hyperlipidemia, medications and general issues was designed and tested. One point was given for every correct answer, whilst zero was given for incorrect answers. Scores ranged from 0 to 28, which were then converted into percentage. This was administered to 77 patients with type 2 diabetes in a tertiary hospital, who were on medication(s) for diabetes and who could understand English (patient group), and to 40 pharmacists (professional group). The DHL knowledge instrument was administered again to the patient group after one month. Excluded were patients less than 18 years old. Flesch reading ease was 60, which is satisfactory, while the mean difficulty factor(SD) was 0.74(0.21), indicating that DHL knowledge instrument was moderately easy. Internal consistency of the instrument was good, with Cronbach's α = 0.791. The test-retest scores showed no significant difference for 26 out of the 28 items, indicating that the questionnaire has achieved stable reliability. The overall mean(SD) knowledge scores was significantly different between the patient and professional groups [74.35(14.88) versus 93.84(6.47), p < 0.001]. This means that the DHL knowledge instrument could differentiate the knowledge levels of participants. The DHL knowledge instrument shows similar psychometric properties as other validated questionnaires. The DHL knowledge instrument shows good promise to be adopted as an instrument for assessing diabetic patients' knowledge concerning their disease conditions and medications in Malaysia.
  BMC Medical Research Methodology 02/2012; 12:18. · 2.67 Impact Factor
• Article: Validation of the English version of the quality of life questionnaire of the European Foundation for Osteoporosis (QUALEFFO) in Malaysia

  Pauline Siew Mei LAI, Siew Siang CHUA, Siew Pheng CHAN, Wah Yun LOW
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  ABSTRACT: Background: Osteoporotic fractures will soon become a common problem in Asian countries including Malaysia, as the growth in the elderly population will be more marked in this region. This leads to loss of independence and reduced quality of life (QOL). QOL is used as an outcome measure in clinical trials to focus the management of diseases on the patient rather than the disease. To date, no such instrument for measuring QOL of osteoporosis patients has been validated in Malaysia.Aim: To investigate the reliability and validity of the English version of the Quality of Life Questionnaire of the European Foundation for Osteoporosis (QUALEFFO) in Malaysia.Methods: QUALEFFO was administered twice to postmenopausal osteoporotic women on alendronate. The patient group consisted of 46 women with back pain while the control group consisted of 42 women without back pain.Results: High internal consistency was seen in all domains in the QUALEFFO with Cronbach of 0.74–0.95 and 0.53–0.89 in the patient and control group, respectively. Factor analysis also showed that each domain consisted of one component except for the social domain. The test-retest reliability showed high correlation coefficient in all domains (0.50–0.90, P < 0.001). Patients with back pain showed significantly worse QOL in the overall total QUALEFFO score compared to the control group (P < 0.0001).Conclusions: The English version of QUALEFFO was found to be reliable and valid for the evaluation of patients with osteoporosis and who understand English in Malaysia. This study also indicates that patients with back pain have poorer QOL.
  International Journal of Rheumatic Diseases 11/2008; 11(4):421 - 429. · 0.81 Impact Factor