Adverse drug reactions and off-label and unlicensed medicines in children: a nested case-control study of inpatients in a pediatric hospital.

BACKGROUND: Off-label and unlicensed (OLUL) prescribing has been prevalent in pediatric practice. Using data from a prospective cohort study of adverse drug reactions (ADRs) among pediatric inpatients, we aimed to test the hypothesis that OLUL status is a risk factor for ADRs. METHODS: A nested case?control study was conducted within a prospective cohort study. Details of all medicines administered were recorded, including information about OLUL status. The odds ratio for OLUL medicines being implicated in a probable or definite ADR was calculated. A multivariate Cox proportional hazards regression model was fitted to the data to assess the influence that OLUL medicine use had on the hazard of an ADR occurring. RESULTS: A total of 10,699 medicine courses were administered to 1,388 patients. The odds ratio (OR) of an OLUL medicine being implicated in an ADR compared with an authorized medicine was 2.25 (95% confidence interval (CI) 1.95 to 2.59). Medicines licensed in children but given to a child below the minimum age or weight had the greatest odds of being implicated in an ADR (19% of courses in this category were implicated, OR 3.54 (95% CI 2.82 to 4.44). Each additional OLUL medicine given significantly increased the hazard of an ADR (hazard ratio (HR) 1.3 95% CI 1.2 to 1.3, P <0.001). Each additional authorized medicine given also significantly increased the hazard (HR 1.2 95% CI 1.2 to 1.3, P <0.001). CONCLUSIONS: OLUL medicines are more likely to be implicated in an ADR than authorized medicines. The number of medicines administered is a risk factor for ADRs highlighting the need to use the lowest number of medicines, at the lowest dose for the shortest period, with continual vigilance by prescribers, in order to reduce the risk of ADRs.

Incidence, characteristics and risk factors of adverse drug reactions in hospitalized children - a prospective observational cohort study of 6,601 admissions.

BACKGROUND: Adverse drug reactions (ADRs) are an important cause of harm in children. Current data are incomplete due to methodological differences between studies: only half of all studies provide drug data, incidence rates vary (0.6% to 16.8%) and very few studies provide data on causality, severity and risk factors of pediatric ADRs. We aimed to determine the incidence of ADRs in hospitalized children, to characterize these ADRs in terms of type, drug etiology, causality and severity and to identify risk factors. METHODS: We undertook a year-long, prospective observational cohort study of admissions to a single UK pediatric medical and surgical secondary and tertiary referral center (Alder Hey, Liverpool, UK). Children between 0 and 16 years 11 months old and admitted for more than 48 hours were included. Observed outcomes were occurrence of ADR and time to first ADR for the risk factor analysis. RESULTS: A total of 5,118 children (6,601 admissions) were included, 17.7% of whom experienced at least one ADR. Opiate analgesics and drugs used in general anesthesia (GA) accounted for more than 50% of all drugs implicated in ADRs. Of these ADRs, 0.9% caused permanent harm or required admission to a higher level of care. Children who underwent GA were at more than six times the risk of developing an ADR than children without a GA (hazard ratio (HR) 6.40; 95% confidence interval (CI) 5.30 to 7.70). Other factors increasing the risk of an ADR were increasing age (HR 1.06 for each year; 95% CI 1.04 to 1.07), increasing number of drugs (HR 1.25 for each additional drug; 95% CI 1.22 to 1.28) and oncological treatment (HR 1.90; 95% CI 1.40 to 2.60). CONCLUSIONS: ADRs are common in hospitalized children and children who had undergone a GA had more than six times the risk of developing an ADR. GA agents and opiate analgesics are a significant cause of ADRs and have been underrepresented in previous studies. This is a concern in view of the increasing number of pediatric short-stay surgeries.

Adverse drug reactions causing admission to a paediatric hospital.

OBJECTIVE(S): To obtain reliable information about the incidence of adverse drug reactions, and identify potential areas where intervention may reduce the burden of ill-health. DESIGN: Prospective observational study. SETTING: A large tertiary children's hospital providing general and specialty care in the UK. PARTICIPANTS: All acute paediatric admissions over a one year period. MAIN EXPOSURE: Any medication taken in the two weeks prior to admission. OUTCOME MEASURES: Occurrence of adverse drug reaction. RESULTS: 240/8345 admissions in 178/6821 patients admitted acutely to a paediatric hospital were thought to be related to an adverse drug reaction, giving an estimated incidence of 2.9% (95% CI 2.5, 3.3), with the reaction directly causing, or contributing to the cause, of admission in 97.1% of cases. No deaths were attributable to an adverse drug reaction. 22.1% (95% CI 17%, 28%) of the reactions were either definitely or possibly avoidable. Prescriptions originating in the community accounted for 44/249 (17.7%) of adverse drug reactions, the remainder originating from hospital. 120/249 (48.2%) reactions resulted from treatment for malignancies. The drugs most commonly implicated in causing admissions were cytotoxic agents, corticosteroids, non-steroidal anti-inflammatory drugs, vaccines and immunosuppressants. The most common reactions were neutropenia, immunosuppression and thrombocytopenia. CONCLUSIONS: Adverse drug reactions in children are an important public health problem. Most of those serious enough to require hospital admission are due to hospital-based prescribing, of which just over a fifth may be avoidable. Strategies to reduce the burden of ill-health from adverse drug reactions causing admission are needed.

Development and inter-rater reliability of the Liverpool adverse drug reaction causality assessment tool.

AIM: To develop and test a new adverse drug reaction (ADR) causality assessment tool (CAT). METHODS: A comparison between seven assessors of a new CAT, formulated by an expert focus group, compared with the Naranjo CAT in 80 cases from a prospective observational study and 37 published ADR case reports (819 causality assessments in total). MAIN OUTCOME MEASURES: Utilisation of causality categories, measure of disagreements, inter-rater reliability (IRR). RESULTS: The Liverpool ADR CAT, using 40 cases from an observational study, showed causality categories of 1 unlikely, 62 possible, 92 probable and 125 definite (1, 62, 92, 125) and 'moderate' IRR (kappa 0.48), compared to Naranjo (0, 100, 172, 8) with 'moderate' IRR (kappa 0.45). In a further 40 cases, the Liverpool tool (0, 66, 81, 133) showed 'good' IRR (kappa 0.6) while Naranjo (1, 90, 185, 4) remained 'moderate'. CONCLUSION: The Liverpool tool assigns the full range of causality categories and shows good IRR. Further assessment by different investigators in different settings is needed to fully assess the utility of this tool.