Initial development and testing of an instrument for patient self-assessment of adverse drug reactions.

PURPOSE: To develop and conduct preliminary testing of a causality assessment tool for patients, for potential use in encouraging both discussions with clinicians about suspected adverse drug reactions (ADRs) and reporting to authorities. METHODS: Ten causality statements, developed from qualitative studies involving patients, with a scoring system allowing categorization, were embedded in a questionnaire which also included a symptom checklist and additional details about one suspected ADR and medicine, selected for causality assessment. Patients with experiences of suspected ADRs were involved in cognitive interviews (15), piloting (20) and psychometric testing (120). Test-retest reliability, construct validity and criterion-related validity were evaluated, through repeated causality assessment, comparison with a visual analogue scale assessing certainty of causality and comparison with causality assessment using World Health Organization-Uppsala Monitoring Centre (WHO-UMC) criteria, respectively. The study involved outpatients at a university hospital in northeast Thailand. RESULTS: Ninety-eight patients completed causality assessment twice: both causality scores (Spearman rs = 0.715; p < 0.001) and causality classification [percentage of positive agreement (PPA) = 68.4; κ = 0.419; p < 0.001] showed satisfactory reliability. Causality scores were positively correlated with certainty of causality (Spearman rs = 0.556; p < 0.01). There was moderate agreement against WHO-UMC criteria [PPA = 70.4; κ = 0.440; p < 0.001]. Of the 91 completing an evaluation, 88% agreed that the tool should be used routinely, 78% agreed that it gave them useful results and 80% agreed that it was easy to use. CONCLUSIONS: This novel instrument has satisfactory psychometric properties and was acceptable to Thai patients, but it requires further testing. It has potential for use in supporting patients with suspected ADRs to discuss these with health professionals, and perhaps to report directly.

A qualitative study to explore how patients identify and assess symptoms as adverse drug reactions.

PURPOSE: To explore how Thai patients assess symptoms as adverse drug reactions (ADRs). METHODS: Out-patients at two hospitals in Thailand previously reporting suspected ADRs to statins were purposively selected to cover factors relevant to the accuracy of ADR reports. Semi-structured interviews explored the mechanisms participants used to work out whether their symptoms were related to their statin. All interviews were audio-recorded, transcribed and independently thematically analyzed by two researchers. RESULTS: One hundred interviews were suitable for analysis; 52 were male, age range was 36 to 77 years (mean ± S.D.: 59.83 ± 9.14) and most (92) were taking other medicines in addition to statins. Patient assessment of symptoms as ADRs fell into two major themes: medicine-related factors and external factors. Timing relationships were mentioned most frequently (74), followed by information received (55), seeing similar symptoms in others (7) and diagnosis through blood tests (4). Use of multiple medicines, consideration of the medicine versus diseases, symptoms occurring with more than one medicine or relieved through treatment reduced confidence in ADR attribution. Many participants proposed alternative explanations for symptoms, including old age. Lack of information and knowledge were obstacles to the assessment process. CONCLUSIONS: Patients assessed possible ADRs most often by considering timing relationships. While they also used medicine information, Thai patients received inadequate information to help them assess their symptoms. Patients expressed uncertainty and difficulties in deciding attribution when concomitant medicines and diseases were involved. The findings could support the development of a patient-friendly systematic tool for identifying and assessing possible ADRs.

Patient reporting of suspected adverse drug reactions to antiepileptic drugs: factors affecting attribution accuracy.

This study was aimed to assess the frequency and number of suspected ADRs reported by patients taking antiepileptic drugs (AEDs) and to explore the factors that may affect patients' symptom attribution accuracy. A validated questionnaire containing an extensively checklist of symptoms was distributed to outpatients prescribed one or more AEDs. Data on concomitant drugs and diseases were obtained from outpatient records. All symptoms identified were assessed for causality. Of 1388 questionnaires distributed to 1214 patients, 830 completed questionnaires were returned (59.8%) from 727 patients. In total, 7815 symptoms were identified on 757 questionnaires (91.2%). Symptom severity ratings were positively related to the number of symptoms reported (p=0.003). Causality assessment found that 71.9% of the symptoms were 'true' ADRs and 28.1% were 'false' ADRs. Attribution accuracy was primarily influenced by the number of symptoms identified and indication for AED therapy, fewer symptoms and use for non-epilepsy indications being associated with greater attribution accuracy.

Management for improving patients' knowledge and understanding about drug allergy.

BACKGROUND: Drug allergy a serious adverse drug reaction commonly concerned in healthcare practice. Inadequate documentation and communication between health providers, and limited health literacy and knowledge in patients could contribute to the re-occurrence of allergic reactions. OBJECTIVE: To evaluate the effectiveness of initiatives aiming to improve patients' knowledge, understanding and behavior in preventing recurrent drug allergy. METHODS: A before-and-after study was conducted at an 800-bed university teaching hospital, involving patients with a history of drug allergy. Questionnaires, completed at baseline and one month after receiving information were used to compare knowledge and understanding of drug allergy and behaviors in relation to drug allergy cards. Patients in Group 1 received a brochure only, but patients in Group 2 also received a pharmacist counseling intervention in addition to the brochure. Outcomes were evaluated within intervention group and between intervention groups. RESULTS: The study included 299 (30.4%) and 100 patients (100.0%) in Groups 1 and 2 respectively who completed the baseline questionnaire, of whom 179 (59.8%) and 96 (96.0%) completed the follow-up questionnaire. At baseline, higher educational levels and possession of a drug allergy card were significantly associated with better knowledge about drug allergy. After intervention, Group 2 had significantly greater increases in mean overall knowledge scores than Group 1 (p<0.01) and also greater increases in the proportions self-reporting carrying and presenting drug allergy cards (p<0.05 and p<0.01). CONCLUSIONS: Pharmacist counseling plus brochure may be more effective than brochure alone in promoting patients' knowledge of drug allergy and drug allergy card importance.

Statin adverse effects: patients' experiences and laboratory monitoring of muscle and liver injuries.

BACKGROUND: Although statins have great benefit on the prevention of cardiovascular diseases with limited adverse effects (AEs), little is known about patients' contribution of AE reports in clinical practice. OBJECTIVES: To explore patients' experiences of statin AEs and related laboratory monitoring in clinical practice. SETTING: Outpatient clinics of two University hospitals in northeast Thailand. METHODS: Generic symptom checklist questionnaires for self-reporting AEs were distributed to patients prescribed simvastatin, atorvastatin, or rosuvastatin at outpatient clinics. Clinical information was obtained from medical records. Reported symptoms were assessed for causality considering previously known statin AEs, concomitant diseases and drugs. MAIN OUTCOME MEASURE: Potential statin AEs reported by patients and monitoring of laboratory parameters related to musculoskeletal and liver disorders. RESULTS: Of the total 718 valid responses, 76.0 % of patients reported at least one symptom, most of which (69.0 %) were probable/possible statin AEs. Musculoskeletal and liver-related symptoms were reported by 283 (39.4 %) and 134 patients (18.7 %), respectively. Probable/possible AEs were categorized in 56.7 % of their musculoskeletal and gastrointestinal symptoms. Majority of patients had at least one laboratory test on initiation of (64.8 %) and during statin treatment (61.8 %). Patients taking atorvastatin or rosuvastatin, and patients with history of chronic renal diseases were more likely to have creatine kinase (CK) monitored on initiation of and during statin treatment. Additionally, taking drugs which could potentially increase muscle injury (OR 1.929, P < 0.01) and self-reporting of musculoskeletal symptoms (OR 1.805, P < 0.01) were associated with CK monitoring during statin treatment. Reporters of musculoskeletal symptoms also had significantly higher mean CK level than those not reporting any musculoskeletal symptoms (207.35 ± 155.40 vs. 143.95 ± 83.07 U/L, respectively; P = 0.037). Patient reporting of liver AEs was not related to alanine aminotransferase (ALT) level and monitoring, however, prior history of liver disorders was significantly associated with monitoring of ALT on initiation of and during statin treatment (OR 5.745 and OR 23.063, respectively; P < 0.01). CONCLUSION: Many patients experienced at least one possible adverse effects on a statin. The findings suggest that laboratory monitoring is relatively selective in relation to risks and patient-reported adverse symptoms.