Mapping Oswestry Disability Index Responses to EQ-5D-3L Utility Values: Are Cost-Utility Results Valid?

OBJECTIVES: To develop and validate approaches for mapping Oswestry Disability Index responses to 3-level version of EQ-5D utility values and to evaluate the impact of using mapped utility values on cost-utility results compared with published regression models. METHODS: Three response mapping approaches were developed in a random sample of 70% of 18 692 patients with low back pain: nonparametric approach (Non-p), nonparametric approach excluding logical inconsistencies (Non-peLI), and ordinal logistic regression (OLR). Performance was assessed in the remaining 30% using R-square (R2), root mean square error (RMSE), and mean absolute error (MAE). To evaluate whether MAEs and their 95% limits of agreement (LA) were clinically relevant, a minimally clinically important difference of 0.074 was used. Probabilities of cost-effectiveness estimated using observed and mapped utility values were compared in 2 economic evaluations. RESULTS: The Non-p performed the best (R2 = 0.43; RMSE = 0.22; MAE = 0.03; 95% LA = -0.40 to 0.47) compared with the Non-peLI (R2 = 0.07; RMSE = 0.29; MAE = -0.15; 95% LA = -0.63 to 0.34) and OLR (R2 = 0.22; RMSE = 0.26; MAE = 0.02; 95% LA = -0.49 to 0.53). MAEs were lower than the minimally clinically important difference for the Non-p and OLR but not for the Non-peLI. Differences in probabilities of cost-effectiveness ranged from 1% to 4% (Non-p), 0.1% to 9% (Non-peLI), and 0.1% to 20% (OLR). CONCLUSIONS: Results suggest that the developed response mapping approaches are not valid for estimating individual patients' 3-level version of EQ-5D utility values, and-depending on the approach-may considerably affect cost-utility results. The developed approaches did not perform better than previously published regression-based models and are therefore not recommended for use in economic evaluations.

A scoping review of statistical methods for trial-based economic evaluations: The current state of play.

The statistical quality of trial-based economic evaluations is often suboptimal, while a comprehensive overview of available statistical methods is lacking. Therefore, this review summarized and critically appraised available statistical methods for trial-based economic evaluations. A literature search was performed to identify studies on statistical methods for dealing with baseline imbalances, skewed costs and/or effects, correlated costs and effects, clustered data, longitudinal data, missing data and censoring in trial-based economic evaluations. Data was extracted on the statistical methods described, their advantages, disadvantages, relative performance and recommendations of the study. Sixty-eight studies were included. Of them, 27 (40%) assessed methods for baseline imbalances, 39 (57%) assessed methods for skewed costs and/or effects, 27 (40%) assessed methods for correlated costs and effects, 18 (26%) assessed methods for clustered data, 7 (10%) assessed methods for longitudinal data, 26 (38%) assessed methods for missing data and 10 (15%) assessed methods for censoring. All identified methods were narratively described. This review provides a comprehensive overview of available statistical methods for dealing with the most common statistical complexities in trial-based economic evaluations. Herewith, it can provide valuable input for researchers when deciding which statistical methods to use in a trial-based economic evaluation.

The statistical approach in trial-based economic evaluations matters: get your statistics together!

BACKGROUND: Baseline imbalances, skewed costs, the correlation between costs and effects, and missing data are statistical challenges that are often not adequately accounted for in the analysis of cost-effectiveness data. This study aims to illustrate the impact of accounting for these statistical challenges in trial-based economic evaluations. METHODS: Data from two trial-based economic evaluations, the REALISE and HypoAware studies, were used. In total, 14 full cost-effectiveness analyses were performed per study, in which the four statistical challenges in trial-based economic evaluations were taken into account step-by-step. Statistical approaches were compared in terms of the resulting cost and effect differences, ICERs, and probabilities of cost-effectiveness. RESULTS: In the REALISE study and HypoAware study, the ICER ranged from 636,744€/QALY and 90,989€/QALY when ignoring all statistical challenges to - 7502€/QALY and 46,592€/QALY when accounting for all statistical challenges, respectively. The probabilities of the intervention being cost-effective at 0€/ QALY gained were 0.67 and 0.59 when ignoring all statistical challenges, and 0.54 and 0.27 when all of the statistical challenges were taken into account for the REALISE study and HypoAware study, respectively. CONCLUSIONS: Not accounting for baseline imbalances, skewed costs, correlated costs and effects, and missing data in trial-based economic evaluations may notably impact results. Therefore, when conducting trial-based economic evaluations, it is important to align the statistical approach with the identified statistical challenges in cost-effectiveness data. To facilitate researchers in handling statistical challenges in trial-based economic evaluations, software code is provided.

Economic evaluation of a combined screening and stepped-care treatment program targeting psychological distress in patients with metastatic colorectal cancer: A cluster randomized controlled trial.

BACKGROUND: Psychological distress is highly prevalent among patients with metastatic colorectal cancer. AIMS: To perform an economic evaluation of a combined screening and treatment program targeting psychological distress in patients with metastatic colorectal cancer in comparison with usual care. DESIGN: Societal costs were collected alongside a cluster randomized controlled trial for 48 weeks. A total of 349 participants were included. SETTING: Participants were recruited from oncology departments at 16 participating hospitals in the Netherlands. METHODS: Outcome measures were the Hospital Anxiety and Depression Scale and quality-adjusted life-years. Missing data were imputed using multiple imputation. Uncertainty was estimated using bootstrapping. Cost-effectiveness planes and cost-effectiveness acceptability curves were estimated to show uncertainty surrounding the cost-effectiveness estimates. Sensitivity analyses were performed to check robustness of results. RESULTS: Between treatment arms, no significant differences were found in Hospital Anxiety and Depression Scale score (mean difference: -0.058; 95% confidence interval: -0.13 to 0.011), quality-adjusted life-years (mean difference: 0.042; 95% confidence interval: -0.015 to 0.099), and societal costs (mean difference: -1152; 95% confidence interval: -5058 to 2214). Cost-effectiveness acceptability curves showed that the probability of cost-effectiveness was 0.64 and 0.74 at willingness-to-pay values of €0 and €10,000 per point improvement on the Hospital Anxiety and Depression Scale, respectively. The probability that the intervention was cost-effective compared to usual care for quality-adjusted life-years was 0.64 and 0.79 at willingness-to-pay values of €0 and €20,000 per quality-adjusted life-year, respectively. CONCLUSION: The intervention is dominant over usual care, primarily due to lower costs in the intervention group. However, there were no statistically significant differences in clinical effects and the uptake of the intervention was quite low. Therefore, widespread implementation cannot be recommended.

Cost-effectiveness of the Namaste care family program for nursing home residents with advanced dementia in comparison with usual care: a cluster-randomized controlled trial.

BACKGROUND: Dementia is a progressive disease that decreases quality of life of persons with dementia and is associated with high societal costs. The burden of caring for persons with dementia also decreases the quality of life of family caregivers. The objective of this study was to assess the societal cost-effectiveness of Namaste Care Family program in comparison with usual care in nursing home residents with advanced dementia. METHODS: Nursing homes were randomized to either Namaste Care Family program or usual care. Outcome measures of the cluster-randomized trial in 231 residents included Quality of Life in Late-Stage Dementia (QUALID) and the Gain in Alzheimer Care Instrument (GAIN) for family caregivers over 12 months of follow-up. Health states were measured using the EQ-5D-3L questionnaire which were translated into utilities. QALYs were calculated by multiplying the amount of time a participant spent in a specific health state with the utility score associated with that health state. Healthcare utilization costs were estimated using standard unit costs, while intervention costs were estimated using a bottom-up approach. Missing cost and effect data were imputed using multiple imputation. Bootstrapped multilevel models were used after multiple imputation. Cost-effectiveness acceptability curves were estimated. RESULTS: The Namaste Care Family program was more effective than usual care in terms of QUALID (- 0.062, 95%CI: - 0.40 to 0.28), QALY (0.0017, 95%CI: - 0.059 to 0.063) and GAIN (0.075, 95%CI: - 0.20 to 0.35). Total societal costs were lower for the Namaste Care Family program as compared to usual care (- 552 €, 95%CI: - 2920 to 1903). However, these differences were not statistically significant. The probability of cost-effectiveness at a ceiling ratio of 0 €/unit of effect extra was 0.70 for the QUALID, QALY and GAIN. CONCLUSIONS: The Namaste Care Family program is dominant over usual care and, thus, cost-effective, although statistical uncertainty was considerable. TRIAL REGISTRATION: Netherlands Trial Register ( http://www.trialregister.nl/trialreg/index.asp , identifier: NL5570, date of registration: 2016/03/23).

A scoping review of studies comparing the medication event monitoring system (MEMS) with alternative methods for measuring medication adherence.

Different methods are available for measuring medication adherence. In this paper, we conducted a scoping review to identify and summarize evidence of all studies comparing the Medication Event Monitoring System (MEMS) with alternative methods for measuring medication adherence. A literature search was performed using the open database www.iAdherence.org that includes all original studies reporting findings from the MEMS. Papers comparing methods for measuring adherence to solid oral formulations were included. Data was extracted using a standardized extraction table. A total of 117 articles fulfilled the inclusion criteria, including 251 comparisons. Most frequent comparisons were against self-report (n = 119) and pill count (n = 59). Similar outcome measures were used in 210 comparisons (84%), among which 78 used dichotomous variables (adherent or not) and 132 used continuous measures (adherence expressed as percentage). Furthermore, 32% of all comparisons did not estimate adherence over the same coverage period and 44% of all comparisons did not use a statistical method or used a suboptimal one. Only eighty-seven (35%) comparisons had similar coverage periods, similar outcome measures and optimal statistical methods. Compared to MEMS, median adherence was grossly overestimated by 17% using self-report, by 8% using pill count and by 6% using rating. In conclusion, among all comparisons of MEMS versus alternative methods for measuring adherence, only a few used adequate comparisons in terms of outcome measures, coverage periods and statistical method. Researchers should therefore use stronger methodological frameworks when comparing measurement methods and be aware that non-electronic measures could lead to overestimation of medication adherence.

Conducting Trial-Based Economic Evaluations Using R: A Tutorial.

Trial-based economic evaluations are increasingly being conducted to support healthcare decision-making. When analysing trial-based economic evaluation data, different methodological challenges may be encountered, including (i) missing data, (ii) correlated costs and effects, (iii) baseline imbalances and (iv) skewness of costs and/or effects. Despite the broad range of methods available to account for these methodological challenges in effectiveness studies, they may not always be directly applicable in trial-based economic evaluations where costs and effects are analysed jointly, and more than one methodological challenge typically needs to be addressed simultaneously. The use of inappropriate methods can bias results and conclusions regarding the cost-effectiveness of healthcare interventions. Eventually, such low-quality evidence can hamper healthcare decision-making, which may in turn result in a waste of already scarce healthcare resources. Therefore, this tutorial aims to provide step-by-step guidance on how to combine appropriate statistical methods for handling the abovementioned methodological challenges using a ready-to-use R script. The theoretical background of the described methods is provided, and their application is illustrated using a simulated trial-based economic evaluation.

Cost-Effectiveness of SGLT2 Inhibitors in a Real-World Population: A MICADO Model-Based Analysis Using Routine Data from a GP Registry.

OBJECTIVE: Sodium-glucose cotransporter 2 inhibitors (SGLT2i) have been shown to reduce the risk of cardiovascular complications, which largely drive diabetes' health and economic burdens. Trial results indicated that SGLT2i are cost effective. However, these findings may not be generalizable to the real-world target population. This study aims to evaluate the cost effectiveness of SGLT2i in a routine care type 2 diabetes population that meets Dutch reimbursement criteria using the MICADO model. METHODS: Individuals from the Hoorn Diabetes Care System cohort (N = 15,392) were filtered to satisfy trial inclusion criteria (including EMPA-REG, CANVAS, and DECLARE-TIMI58) or satisfy the current Dutch reimbursement criteria for SGLT2i. We validated a health economic model (MICADO) by comparing simulated and observed outcomes regarding the relative risks of events in the intervention and comparator arm from three trials, and used the validated model to evaluate the long-term health outcomes using the filtered cohorts' baseline characteristics and treatment effects from trials and a review of observational studies. The incremental cost-effectiveness ratio (ICER) of SGLT2i, compared with care-as-usual, was assessed from a third-party payer perspective, measured in euros (2021 price level), using a discount rate of 4% for costs and 1.5% for effects. RESULTS: From Dutch individuals with diabetes in routine care, 15.8% qualify for the current Dutch reimbursement criteria for SGLT2i. Their characteristics were significantly different (lower HbA1c, higher age, and generally more preexisting complications) than trial populations. After validating the MICADO model, we found that lifetime ICERs of SGLT2i, when compared with usual care, were favorable (< €20,000/QALY) for all filtered cohorts, resulting in an ICER of €5440/QALY using trial-based treatment effect estimates in reimbursed population. Several pragmatic scenarios were tested, the ICERs remained favorable. CONCLUSIONS: Although the Dutch reimbursement indications led to a target group that deviates from trial populations, SGLT2i are likely to be cost effective when compared with usual care.

Cost-effectiveness of twice-weekly versus once-weekly sessions of cognitive-behavioural therapy and interpersonal psychotherapy for depression at 12 months after start of treatment: randomised controlled trial.

BACKGROUND: Cost-effective treatments are needed to reduce the burden of depression. One way to improve the cost-effectiveness of psychotherapy might be to increase session frequency, but keep the total number of sessions constant. AIM: To evaluate the cost-effectiveness of twice-weekly compared with once-weekly psychotherapy sessions after 12 months, from a societal perspective. METHOD: An economic evaluation was conducted alongside a randomised controlled trial comparing twice-weekly versus once-weekly sessions of psychotherapy (cognitive-behavioural therapy or interpersonal psychotherapy) for depression. Missing data were handled by multiple imputation. Statistical uncertainty was estimated with bootstrapping and presented with cost-effectiveness acceptability curves. RESULTS: Differences between the two groups in depressive symptoms, physical and social functioning, and quality-adjusted life-years (QALY) at 12-month follow-up were small and not statistically significant. Total societal costs in the twice-weekly session group were higher, albeit not statistically significantly so, than in the once-weekly session group (mean difference €2065, 95% CI -686 to 5146). The probability that twice-weekly sessions are cost-effective compared with once-weekly sessions was 0.40 at a ceiling ratio of €1000 per point improvement in Beck Depression Inventory-II score, 0.32 at a ceiling ratio of €50 000 per QALY gained, 0.23 at a ceiling ratio of €1000 per point improvement in physical functioning score and 0.62 at a ceiling ratio of €1000 per point improvement in social functioning score. CONCLUSIONS: Based on the current results, twice-weekly sessions of psychotherapy for depression are not cost-effective over the long term compared with once-weekly sessions.

Cost-effectiveness of general practitioner- versus surgeon-led colon cancer survivorship care: an economic evaluation alongside a randomised controlled trial.

PURPOSE: The aim of this study is to assess cost-effectiveness of general practitioner (GP) versus surgeon-led colon cancer survivorship care from a societal perspective. METHODS: We performed an economic evaluation alongside the I CARE study, which included 303 cancer patients (stages I-III) who were randomised to survivorship care by a GP or surgeon. Questionnaires were administered at baseline, 3-, 6-, 12-, 24- and 36-months. Costs included healthcare costs (measured by iMTA MCQ) and lost productivity costs (SF-HLQ). Disease-specific quality of life (QoL) was measured using EORTC QLQ-C30 summary score and general QoL using EQ-5D-3L quality-adjusted life years (QALYs). Missing data were imputed. Incremental cost-effectiveness ratios (ICERs) were calculated to relate costs to effects on QoL. Statistical uncertainty was estimated using bootstrapping. RESULTS: Total societal costs of GP-led care were significantly lower compared to surgeon-led care (mean difference of - €3895; 95% CI - €6113; - €1712). Lost productivity was the main contributor to the difference in societal costs (- €3305; 95% CI - €5028; - €1739). The difference in QLQ-C30 summary score over time between groups was 1.33 (95% CI - 0.049; 3.15). The ICER for QLQ-C30 was - 2073, indicating that GP-led care is dominant over surgeon-led care. The difference in QALYs was - 0.021 (95% CI - 0.083; 0.040) resulting in an ICER of 129,164. CONCLUSIONS: GP-led care is likely to be cost-effective for disease-specific QoL, but not for general QoL. IMPLICATIONS FOR CANCER SURVIVORS: With a growing number of cancer survivors, GP-led survivorship care could help to alleviate some of the burden on more expensive secondary healthcare services.

Cost-effectiveness and return-on-investment of C-reactive protein point-of-care testing in comparison with usual care to reduce antibiotic prescribing for lower respiratory tract infections in nursing homes: a cluster randomised trial.

OBJECTIVES: C-reactive protein point-of-care testing (CRP POCT) is a promising diagnostic tool to guide antibiotic prescribing for lower respiratory tract infections (LRTI) in nursing home residents. This study aimed to evaluate cost-effectiveness and return-on-investment (ROI) of CRP POCT compared with usual care for nursing home residents with suspected LRTI from a healthcare perspective. DESIGN: Economic evaluation alongside a cluster randomised, controlled trial. SETTING: 11 Dutch nursing homes. PARTICIPANTS: 241 nursing home residents with a newly suspected LRTI. INTERVENTION: Nursing home access to CRP POCT (POCT-guided care) was compared with usual care without CRP POCT (usual care). MAIN OUTCOME MEASURES: The primary outcome measure for the cost-effectiveness analysis was antibiotic prescribing at initial consultation, and the secondary outcome was full recovery at 3 weeks. ROI analyses included intervention costs, and benefits related to antibiotic prescribing. Three ROI metrics were calculated: Net Benefits, Benefit-Cost-Ratio and Return-On-Investment. RESULTS: In POCT-guided care, total costs were on average €32 higher per patient, the proportion of avoided antibiotic prescribing was higher (0.47 vs 0.18; 0.30, 95% CI 0.17 to 0.42) and the proportion of fully recovered patients statistically non-significantly lower (0.86 vs 0.91; -0.05, 95% CI -0.14 to 0.05) compared with usual care. On average, an avoided antibiotic prescription was associated with an investment of €137 in POCT-guided care compared with usual care. Sensitivity analyses showed that results were relatively robust. Taking the ROI metrics together, the probability of financial return was 0.65. CONCLUSION: POCT-guided care effectively reduces antibiotic prescribing compared with usual care without significant effects on recovery rates, but requires an investment. Future studies should take into account potential beneficial effects of POCT-guided care on costs and health outcomes related to antibiotic resistance. TRIAL REGISTRATION NUMBER: NL5054.

Cost-effectiveness of custom-made insoles versus usual care in patients with plantar heel pain in primary care: cost-effectiveness analysis of a randomised controlled trial.

OBJECTIVES: To evaluate the cost-effectiveness of custom-made insoles compared with general practitioner (GP)-led usual care after 26 weeks of follow-up in individuals with plantar heel pain (PHP) from a societal perspective. DESIGN: Cost-effectiveness analysis of a double-blinded randomised controlled trial. SETTING: General practice in the Netherlands. PARTICIPANTS: 116 participants with PHP for at least 2 weeks, aged 18-65 years and presenting to the GP. INTERVENTIONS: Participants were randomised to GP-led usual care (n=46) or referral to a podiatrist for treatment with a custom-made insole (n=70). Participant randomised to a sham insole (n=69) were excluded from this analysis. PRIMARY AND SECONDARY OUTCOMES: Outcomes comprised pain during rest and activity, and quality of life. Costs included healthcare and lost productivity costs. Statistical uncertainty was estimated using bootstrapping and presented using cost-effectiveness acceptability curves. RESULTS: Participants in the custom-made insole group experienced statistically significant more pain during activity at 26 weeks than participants in the usual care group (overall effect 1.06; 95% CI 0.36 to 1.75). There were no significant differences between groups in other outcomes. Total societal costs in the custom-made insole group were non-significantly higher than in the usual care group (mean difference €376; 95% CI -€1775 to €2038). The intervention with custom-made insoles was dominated by usual care by the GP (ie, more expensive and less effective) for pain during activity and quality of life outcomes. For the outcome pain at rest, the intervention was more expensive and more effective than usual care. However, the maximum probability of cost-effectiveness was only 0.59 at very high ceiling ratios. CONCLUSIONS: These findings show that that custom-made insoles are not cost-effective in comparison with GP-led usual care. Clinicians should be reserved in prescribing custom-made insoles for PHP as a primary intervention. TRIAL REGISTRATION NUMBER: NTR5346.

Cost-effectiveness of single-layer versus double-layer uterine closure during caesarean section on postmenstrual spotting: economic evaluation alongside a randomised controlled trial.

OBJECTIVE: To evaluate the cost-effectiveness of double-layer compared with single-layer uterine closure after a first caesarean section (CS) from a societal and healthcare perspective. DESIGN: Economic evaluation alongside a multicentre, double-blind, randomised controlled trial. SETTING: 32 hospitals in the Netherlands, 2016-2018. PARTICIPANTS: 2292 women ≥18 years undergoing a first CS were randomly assigned (1:1). Exclusion criteria were: inability for counselling, previous uterine surgery, known menstrual disorder, placenta increta or percreta, pregnant with three or more fetuses. 1144 women were assigned to single-layer and 1148 to double-layer closure. We included 1620 women with a menstrual cycle in the main analysis. INTERVENTIONS: Single-layer unlocked uterine closure and double-layer unlocked uterine closure with the second layer imbricating the first. MAIN OUTCOME MEASURES: Spotting days, quality-adjusted life-years (QALYs), and societal costs at 9 months of follow-up. Missing data were imputed using multiple imputation. RESULTS: No significant differences were found between single-layer versus double-layer closure in mean spotting days (1.44 and 1.39 days; mean difference (md) -0.056, 95% CI -0.374 to 0.263), QALYs (0.663 and 0.658; md -0.005, 95% CI -0.015 to 0.005), total healthcare costs (€744 and €727; md €-17, 95% CI -273 to 143), and total societal costs (€5689 and €5927; md €238, 95% CI -624 to 1108). The probability of the intervention being cost-effective at willingness-to-pay of €0, €10 000 and €20 000/QALY gained was 0.30, 0.27 and 0.25, respectively, (societal perspective), and 0.55, 0.41 and 0.32, respectively, (healthcare perspective). CONCLUSION: Double-layer uterine closure is not cost-effective compared with single-layer uterine closure from both perspectives. If this is confirmed by our long-term reproductive follow-up, we suggest to adjust uterine closure technique guidelines. TRIAL REGISTRATION NUMBER: NTR5480/NL5380.

Taking the Analysis of Trial-Based Economic Evaluations to the Next Level: The Importance of Accounting for Clustering.

OBJECTIVES: The aim of this study was to assess the performance and impact of multilevel modelling (MLM) compared with ordinary least squares (OLS) regression in trial-based economic evaluations with clustered data. METHODS: Three thousand datasets with balanced and unbalanced clusters were simulated with correlation coefficients between costs and effects of - 0.5, 0, and 0.5, and intraclass correlation coefficients (ICCs) varying between 0.05 and 0.30. Each scenario was analyzed using both MLM and OLS. Statistical uncertainty around MLM and OLS estimates was estimated using bootstrapping. Performance measures were estimated and compared between approaches, including bias, root mean squared error (RMSE) and coverage probability. Cost and effect differences, and their corresponding confidence intervals and standard errors, incremental cost-effectiveness ratios, incremental net-monetary benefits and cost-effectiveness acceptability curves were compared. RESULTS: Cost-effectiveness outcomes were similar between OLS and MLM. MLM produced larger statistical uncertainty and coverage probabilities closer to nominal levels than OLS. The higher the ICC, the larger the effect on statistical uncertainty between MLM and OLS. Significant cost-effectiveness outcomes as estimated by OLS became non-significant when estimated by MLM. At all ICCs, MLM resulted in lower probabilities of cost effectiveness than OLS, and this difference became larger with increasing ICCs. Performance measures and cost-effectiveness outcomes were similar across scenarios with varying correlation coefficients between costs and effects. CONCLUSIONS: Although OLS produced similar cost-effectiveness outcomes, it substantially underestimated the amount of variation in the data compared with MLM. To prevent suboptimal conclusions and a possible waste of scarce resources, it is important to use MLM in trial-based economic evaluations when data are clustered.

What do national pharmacoeconomic guidelines recommend regarding the statistical analysis of trial-based economic evaluations?

Introduction: The statistical quality of many trial-based economic evaluations is poor. When conducting trial-based economic evaluations, researchers often turn to national pharmacoeconomic guidelines for guidance. Therefore, this study reviewed which recommendations are currently given by national pharmacoeconomic guidelines on the statistical analysis of trial-based economic evaluations.Areas covered: 40 national pharmacoeconomic guidelines were identified. Data were extracted on the guidelines' recommendations on how to deal with baseline imbalances, skewed costs, correlated costs and effects, clustering of data, longitudinal data, and missing data in trial-based economic evaluations. Four guidelines (10%) were found to include recommendations on how to deal with baseline imbalances, five (13%) on how to deal with skewed costs, and seven (18%) on how to deal with missing data. Recommendations were very general in nature and recommendations on dealing with correlated costs and effects, clustering of data, and longitudinal data were lacking.Expert opinion: Current national pharmacoeconomic guidelines provide little to no guidance on how to deal with the statistical challenges to trial-based economic evaluations. Since the use of suboptimal statistical methods may lead to biased results, and, therefore, possibly to a waste of scarce resources, national agencies are advised to include more statistical guidance in their pharmacoeconomic guidelines.

Reporting and Analysis of Trial-Based Cost-Effectiveness Evaluations in Obstetrics and Gynaecology.

BACKGROUND AND OBJECTIVES: The aim was to systematically review whether the reporting and analysis of trial-based cost-effectiveness evaluations in the field of obstetrics and gynaecology comply with guidelines and recommendations, and whether this has improved over time. DATA SOURCES AND SELECTION CRITERIA: A literature search was performed in MEDLINE, the NHS Economic Evaluation Database (NHS EED) and the Health Technology Assessment (HTA) database to identify trial-based cost-effectiveness evaluations in obstetrics and gynaecology published between January 1, 2000 and May 16, 2017. Studies performed in middle- and low-income countries and studies related to prevention, midwifery, and reproduction were excluded. DATA COLLECTION AND ANALYSIS: Reporting quality was assessed using the Consolidated Health Economic Evaluation Reporting Standard (CHEERS) statement (a modified version with 21 items, as we focused on trial-based cost-effectiveness evaluations) and the statistical quality was assessed using a literature-based list of criteria (8 items). Exploratory regression analyses were performed to assess the association between reporting and statistical quality scores and publication year. RESULTS: The electronic search resulted in 5482 potentially eligible studies. Forty-five studies fulfilled the inclusion criteria, 22 in obstetrics and 23 in gynaecology. Twenty-seven (60%) studies did not adhere to 50% (n = 10) or more of the reporting quality items and 32 studies (71%) did not meet 50% (n = 4) or more of the statistical quality items. As for the statistical quality, no study used the appropriate method to assess cost differences, no advanced methods were used to deal with missing data, and clustering of data was ignored in all studies. No significant improvements over time were found in reporting or statistical quality in gynaecology, whereas in obstetrics a significant improvement in reporting and statistical quality was found over time. LIMITATIONS: The focus of this review was on trial-based cost-effectiveness evaluations in obstetrics and gynaecology, so further research is needed to explore whether results from this review are generalizable to other medical disciplines. CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS: The reporting and analysis of trial-based cost-effectiveness evaluations in gynaecology and obstetrics is generally poor. Since this can result in biased results, incorrect conclusions, and inappropriate healthcare decisions, there is an urgent need for improvement in the methods of cost-effectiveness evaluations in this field.