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Marshall MR, Curd S, Kennedy J, Khatri D, Lee S, Pireva K, Taule’alo O, Tiavale-Moore P, Wolley MJ, Ma TM, Kam AL, Suh JS, Aspden TJ. Structural Equation Modelling to Identify Psychometric Determinants of Medication Adherence in a Survey of Kidney Dialysis Patients. Patient Prefer Adherence 2024; 18:855-878. [PMID: 38645697 PMCID: PMC11032681 DOI: 10.2147/ppa.s454248] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 03/26/2024] [Indexed: 04/23/2024] Open
Abstract
Purpose Medication non-adherence in dialysis patients is associated with increased mortality and higher healthcare costs. We assessed whether medication adherence is influenced by specific psychometric constructs measuring beliefs about the necessity for medication and concerns about them. We also tested whether medication knowledge, health literacy, and illness perceptions influenced this relationship. Patients and Methods This study is based on data from a cross-sectional in-person questionnaire, administered to a random sample of all adult dialysis patients at a teaching hospital. The main outcome was self-assessed medication adherence (8-Item Morisky Medication Adherence Scale). The predictors were: concerns about medications and necessity for medication (Beliefs About Medication Questionnaire); health literacy; medication knowledge (Medication Knowledge Evaluation Tool); cognitive, emotional, and comprehensibility Illness perceptions (Brief Illness Perception Questionnaire). Path analysis was performed using structural equations in both covariance and variance-based models. Results Necessity for medication increased (standardized path coefficient [β] 0.30 [95% CI 0.05, 0.54]) and concerns about medication decreased (standardized β -0.33 [-0.57, -0.09]) medication adherence, explaining most of the variance in outcome (r2=0.95). Medication knowledge and cognitive illness perceptions had no effects on medication adherence, either directly or indirectly. Higher health literacy, greater illness comprehension, and a more positive emotional view of their illness had medium-to-large sized effects in increasing medication adherence. These were indirect rather and direct effects mediated by decreases in concerns about medications (standardized β respectively -0.40 [-0.63,-0.16], -0.60 [-0.85, -0.34], -0.33 [-0.52, -0.13]). Conclusion Interventions that reduce patients' concerns about their medications are likely to improve adherence, rather than interventions that increase patients' perceived necessity for medication. Improving patients' general health literacy and facilitating a better understanding and more positive perception of the illness can probably achieve this. Our study is potentially limited by a lack of generalizability outside of the population and setting in which it was conducted.
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Affiliation(s)
- Mark R Marshall
- School of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- Department of Medicine, Tauranga Hospital, Hauora a Toi Bay of Plenty, Tauranga, New Zealand
- Department of Renal Medicine, Middlemore Hospital, Counties Manukau Health, Auckland, New Zealand
| | - Samantha Curd
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Julia Kennedy
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Dharni Khatri
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Sophia Lee
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Krenare Pireva
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Olita Taule’alo
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Porsche Tiavale-Moore
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - Martin J Wolley
- Department of Renal Medicine, Middlemore Hospital, Counties Manukau Health, Auckland, New Zealand
- Endocrine Hypertension Research Centre, University of Queensland Frazer Institute, Greenslopes and Princess Alexandra Hospitals, Brisbane, Queensland, Australia
- Department of Nephrology, Royal Brisbane and Women’s Hospital, Brisbane, Queensland, Australia
| | - Tian M Ma
- Department of Renal Medicine, Middlemore Hospital, Counties Manukau Health, Auckland, New Zealand
- Institute for Innovation + Improvement, North Shore Hospital, Auckland, New Zealand
| | - Angela L Kam
- Department of Renal Medicine, Middlemore Hospital, Counties Manukau Health, Auckland, New Zealand
- Barts Health NHS Trust, London, UK
| | - Jun S Suh
- Department of Renal Medicine, Middlemore Hospital, Counties Manukau Health, Auckland, New Zealand
| | - Trudi J Aspden
- School of Pharmacy, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
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Hood CJ, Wolley MJ, Kam AL, Kendrik-Jones JC, Marshall MR. Feasibility study of colestipol as an oral phosphate binder in hemodialysis patients. Nephrology (Carlton) 2015; 20:250-6. [PMID: 25557531 DOI: 10.1111/nep.12388] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/21/2014] [Indexed: 01/13/2023]
Abstract
BACKGROUND Currently available calcium- and aluminium-based phosphate binders are dose limited because of potential toxicity, and newer proprietary phosphate binders are expensive. We examined phosphate-binding effects of the bile acid sequestrant colestipol, a non-proprietary drug that is in the same class as sevelamer. METHODS The trial was an 8 week prospective feasibility study in stable hemodialysis patients using colestipol as the only phosphate binder, preceded and followed by a washout phase of all other phosphate binders. The primary study endpoint was weekly measurements of serum phosphate. Secondary endpoints were serum calcium, lipids and coagulation status. Analyses used random effects mixed models. RESULTS Thirty patients were screened for participation of which 26 met criteria for treatment. At a mean dose of 8.8 g/24 h of colestipol by study end, serum phosphate dropped from 2.24 to 1.96 mmol/L (P < 0.001). Three patients required calcium supplementation. LDL cholesterol dropped from 1.75 to 1.2 mmol/L (P < 0.001). Three patients dropped out because of side effects or intolerance of the required dose. CONCLUSION The results support the feasibility of a larger trial to determine the efficacy of colestipol as a phosphate binder and that other non-proprietary anion-exchange resins may also warrant investigation.
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Affiliation(s)
- Christopher J Hood
- Department of Renal Medicine, Counties Manukau District Health Board, Shanghai, China; Faculty of Medical and Health Sciences, University of Auckland, Shanghai, China
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Aspden T, Wolley MJ, Ma TM, Rajah E, Curd S, Kumar D, Lee S, Pireva K, Taule'alo O, Tiavale P, Kam AL, Suh JS, Kennedy J, Marshall MR. Understanding barriers to optimal medication management for those requiring long-term dialysis: rationale and design for an observational study, and a quantitative description of study variables and data. BMC Nephrol 2015; 16:102. [PMID: 26162369 PMCID: PMC4499205 DOI: 10.1186/s12882-015-0097-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2014] [Accepted: 06/25/2015] [Indexed: 12/05/2022] Open
Abstract
Background Rates of medication non-adherence in dialysis patients are high, and improving adherence is likely to improve outcomes. Few data are available regarding factors associated with medication adherence in dialysis patients, and these data are needed to inform effective intervention strategies. Methods/design This is an observational cross-sectional study of a multi-ethnic dialysis cohort from New Zealand, with the main data collection tool being an interviewer-assisted survey. A total of 100 participants were randomly sampled from a single centre, with selection stratified by ethnicity and dialysis modality (facility versus home). The main outcome measure is self-reported medication adherence using the Morisky 8-Item Medication Adherence Scale (MMAS-8). Study data include demographic, clinical, social and psychometric characteristics, the latter being constructs of health literacy, medication knowledge, beliefs about medications, and illness perceptions. Psychometric constructs were assessed through the following survey instruments; health literacy screening questions, the Medication Knowledge Evaluation Tool (Okuyan et al.), the Beliefs about Medication Questionnaire (Horne et al.), the Brief Illness Perception Questionnaire (Broadbent et al.). Using the study data, reliability analysis for internal consistency is satisfactory for the scales evaluating health literacy, medication knowledge, and beliefs about medications, with Chronbach’s α > 0.7 for all. Reliability analysis indicated poor internal consistency for scales relating to illness perceptions. MMAS-8 and all psychometric scores are normally distributed in the study data. Discussion This study will provide important information on the factors involved in medication non-adherence in New Zealand dialysis patients. The resulting knowledge will inform long-term initiatives to reduce medication non-adherence in dialysis patients, and help ensure that they are addressing appropriate and evidence based targets for intervention. Electronic supplementary material The online version of this article (doi:10.1186/s12882-015-0097-2) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Trudi Aspden
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, 85 Park Rd, Auckland, 1142, New Zealand.
| | - Martin J Wolley
- School of Medicine, University of Queensland, 288 Herston Road, Brisbane, 4006, Australia.
| | - Tian M Ma
- Department of Renal Medicine, Counties Manukau District Health Board, Hospital Road, Otahuhu, Auckland, 1640, New Zealand.
| | - Edwin Rajah
- Marketing Department, Faculty of Business, Auckland University of Technology, 46 Wakefield St, Auckland, 1010, New Zealand.
| | - Samantha Curd
- Formerly of the School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, 85 Park Rd, Auckland, 1142, New Zealand.
| | - Dharni Kumar
- Formerly of the School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, 85 Park Rd, Auckland, 1142, New Zealand.
| | - Sophia Lee
- Formerly of the School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, 85 Park Rd, Auckland, 1142, New Zealand.
| | - Krenare Pireva
- Formerly of the School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, 85 Park Rd, Auckland, 1142, New Zealand.
| | - Olita Taule'alo
- Formerly of the School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, 85 Park Rd, Auckland, 1142, New Zealand.
| | - Porsche Tiavale
- Formerly of the School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, 85 Park Rd, Auckland, 1142, New Zealand.
| | - Angela L Kam
- Pharmacy Services, Counties Manukau District Health Board, Hospital Road, Otahuhu, Auckland, 1640, New Zealand.
| | - Jun S Suh
- Department of Renal Medicine, Counties Manukau District Health Board, Hospital Road, Otahuhu, Auckland, 1640, New Zealand.
| | - Julia Kennedy
- School of Pharmacy, Faculty of Medical and Health Sciences, The University of Auckland, 85 Park Rd, Auckland, 1142, New Zealand.
| | - Mark R Marshall
- School of Medicine, Faculty of Medical and Health Sciences, The University of Auckland, 85 Park Rd, Auckland, 1142, New Zealand.
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Liebman HA, Kashani N, Sutherland D, McGehee W, Kam AL. The factor V Leiden mutation increases the risk of venous thrombosis in patients with inflammatory bowel disease. Gastroenterology 1998; 115:830-4. [PMID: 9753484 DOI: 10.1016/s0016-5085(98)70253-7] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS Thromboembolic disease is a significant cause of morbidity and mortality in patients with inflammatory bowel disease (IBD). The aim of this study was to determine the incidence and possible association of the factor V Leiden mutation with the development of thrombosis in patients with IBD. METHODS This retrospective study included 11 patients with IBD and arterial or venous thrombosis and 51 patients with IBD and no history of thrombosis who were matched for age, sex, ethnic/racial origin, and type of IBD (controls). The presence of the factor V Leiden mutation was determined by coagulation assay and confirmed by a polymerase chain reaction method. RESULTS Four of 11 IBD patients (36%) with thrombosis and 2 of 51 IBD controls (4%) were heterozygotes for the factor V Leiden mutation (relative risk, 14.00; 95% confidence interval, 1.55-169.25; P = 0.009, Fisher exact test). All thrombotic events in the patients with activated protein C resistance were venous with a calculated prevalence of 50% (4 of 8 patients) and a relative risk of venous thrombosis in IBD patients with factor V Leiden of 23 (95% confidence interval, 2-294; P = 0.005). CONCLUSIONS In patients with IBD, inheritance of the factor V Leiden mutation results in a significant increased risk of venous thrombosis.
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Affiliation(s)
- H A Liebman
- Division of Hematology, Department of Medicine, University of Southern California School of Medicine, Los Angeles, California, USA.
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