Evaluating beneficial drug effects in a non-interventional setting: a review of effectiveness studies based on Swedish Prescribed Drug Register data

Bleeding in patients on concurrent treatment with a selective serotonin reuptake inhibitor (SSRI) and low-dose acetylsalicylic acid (ASA) compared with SSRI or low-dose ASA alone-A systematic review and meta-analysis

AIMS

The aim of this study was to systematically review whether concurrent treatment with an SSRI and low-dose ASA increases the risk of bleeding compared with treatment with an SSRI alone or ASA alone.

METHODS

Medline, Embase, the Cochrane Library, PsycINFO and Web of Science (from database inception to January 2023) were searched according to PICO: P = patients on treatment with an SSRI and/or low-dose ASA; I = intervention: SSRI + ASA; C = comparison: ASA or SSRI alone; O = outcomes: bleeding/major bleeding. The included articles were assessed using checklists. Studies without major risk of bias formed the basis for the conclusions. Extracted data were pooled using random-effects meta-analyses. Certainty of evidence was assessed according to GRADE.

RESULTS

Twenty-four studies met the PICO and were included. One randomized and six nonrandomized studies were assessed not to have major risk of bias. Regarding SSRI + ASA vs. ASA only, the pooled hazard ratio of three nonrandomized studies (n = 38 467) was 1.37 (95% confidence interval: 1.10; 1.70; I2 = 0%), and the pooled odds ratio of two nonrandomized studies (n = 28 296) was 0.95 (0.77; 1.19; I2 = 0%). Regarding SSRI + ASA vs. SSRI only, the randomized controlled trial (n = 1048) reported a hazard ratio of 1.82 (0.66; 5.02), the hazard ratio being 1.60 (1.24; 2.06) for ASA vs. placebo in patients without SSRI treatment; and one nonrandomized controlled study (n = 18 920) reported an incidence rate ratio of 1.03 (0.96; 1.12).

CONCLUSIONS

The compiled evidence was too uncertain to support an interaction when an SSRI is added to low-dose ASA. Low-dose ASA added to an SSRI may imply an increased risk of bleeding primarily attributable to the initiation of ASA.

Quality of clinical studies present in the package inserts of coagulation factors used in the treatment of hemophilia

OBJECTIVE

To identify and analyze the quality of scientific evidence from clinical efficacy studies present in the package inserts of coagulation factors, used in the treatment of hemophilia A and B.

METHODS

Documentary study developed in two stages. The first stage consisted of identifying the medicine packages inserts electronically registered in the Brazilian Health Regulatory Agency, and analyzing the availability of the bibliographic references cited therein. This analysis was conducted in the PubMed, SciELO, Google Scholar, and Web of Science databases. The second step was the analysis of the methodological quality of the efficacy studies. Two trained researchers used the Cochrane Collaboration Risk of Bias version 5.1.0 tools for methodological quality analysis, and Review Manager 5.4 software to generate the risk of bias graph.

RESULTS

Of the 17 medicines listed, 7 had referenced package inserts. Of these, 10 studies were eligible for analysis of methodological quality. More than half of the analyzed studies did not control for selection, performance, and detection bias. A total of 100% controlled attrition and reporting biases, and 50% had a high risk of conflict of interest.

CONCLUSION

The biases present are significant and may have influenced the overestimation of the effects of the outcomes of each of the studies.

Anti-inflammatory, antibacterial and immunomodulatory treatment in children with symptoms corresponding to the research condition PANS (Pediatric Acute-onset Neuropsychiatric Syndrome): A systematic review

OBJECTIVE

To assess effects of treatment against a hypothesized neuroinflammation in children with symptoms corresponding to the research condition Pediatric Acute-onset Neuropsychiatric Syndrome (PANS) which is not included in current diagnostic systems.

METHODS

Systematic literature searches were performed (1998 to June 2020) in PubMed, Embase, the Cochrane Library, CINAHL, PsycInfo, and HTA databases. Inclusion criteria: patients (P) were children (<18 years) with PANS; intervention (I)/comparison (C) was use of, versus no use of, anti-inflammatory, antibacterial or immunomodulating treatments; outcomes (O) were health-related quality of life (HRQL), level of functioning, symptom change, and complications.

RESULTS

Four randomised controlled trials (RCTs) and three non-RCTs, including 23 to 98 patients, fulfilled the PICO. HRQL was not investigated in any study. Regarding level of functioning, two RCTs investigated antibiotics (penicillin V, azithromycin) and one RCT investigated immunomodulating treatments (intravenous immunoglobulins (IVIG), plasma exchange). Regarding symptoms, two non-RCTs investigated anti-inflammatory treatment (cyclooxygenase (COX) inhibitors, corticosteroids), two RCTs and one non-RCT investigated antibiotics (penicillin V, azithromycin), and two RCTs investigated immunomodulating treatments (IVIG, plasma exchange). Complications, reported in five studies, were consistent with those listed in the summary of products characteristics (SPC). All studies were assessed to have some or major problems regarding directness, the absence of an established diagnosis contributing to clinical diversity in the studied populations. All studies were assessed to have major risk of bias, including selection and detection biases. Due to clinical and methodological diversity, meta-analyses were not performed.

CONCLUSION

This systematic review reveals very low certainty of evidence of beneficial effects, and moderate certainty of evidence of adverse effects, of anti-inflammatory, antibacterial or immunomodulating treatments in patients with symptoms corresponding to the research condition PANS. Available evidence neither supports nor excludes potential beneficial effects, but supports that such treatment can result in adverse effects.

REGISTRATION

PROSPERO (CRD42020155714).

Personalised medicine and the decision to withhold chemotherapy in early breast cancer with intermediate risk of recurrence - a systematic review and meta-analysis

PURPOSE

To assess the evidence for decision making, at the health care and the patient levels, regarding the use of gene expression assays to inform chemotherapy decisions in breast cancer patients with intermediate clinical risk of recurrence.

METHODS

Systematic literature searches were performed (January 2002-April 2020) in Medline, Embase, PubMed, Cochrane Library, PsycINFO and HTA databases.

INCLUSION CRITERIA

patients (P) were individuals with post-surgical breast cancer at intermediate clinical risk of recurrence; intervention (I)/comparison (C) was (i) use of, versus no use of, a gene expression assay and (ii) withholding versus providing chemotherapy; outcomes (O) were overall survival (OS), health-related quality of life (HRQL), and recurrence. Randomised controlled trials (RCTs) and non-RCTs were included. Random-effects meta-analyses were performed where possible.

RESULTS

Three inconclusive non-RCTs, respectively, compared OS and recurrence with and without a gene expression assay. No studies investigated HRQL. Regarding the comparison withholding versus providing chemotherapy based on a gene expression assay, one RCT and four non-RCTs evaluated OS. In the RCT, 93.9% (I) versus 93.8% (C) were alive at 9 years. Three RCTs and seven non-RCTs evaluated recurrence. Three RCTs could be pooled regarding distant recurrence; 4.29% versus 3.88% had such an event (risk ratio: 1.12 (95% confidence interval: 0.90 to 1.39).

CONCLUSION

Regarding the use of gene expression assays in breast cancer, evidence on patient effects, informing patient-level chemotherapy decision making, is available. However, evidence for prioritisation at the overall health care level, i.e. use of, versus no use of, such assays, is largely lacking.

Efficacy gap between phase II and subsequent phase III studies in oncology

Aims

There is a trend for more flexibility in timing of evidence generation in relation to marketing authorization, including the option to complete phase III trials after authorization or not at all. This paper investigated the relation between phase II and III clinical trial efficacy in oncology.

Methods

All oncology drugs approved by the European Medicines Agency (2007–2016) were included. Phase II and phase III trials were matched based on indication and treatment and patient characteristics. Reported objective response rates (ORR), median progression‐free survival (PFS) and median overall survival (OS) were analysed through weighted mixed‐effects regression with previous treatment, treatment regimen, blinding, randomization, marketing authorization type and cancer type as covariates.

Results

A total of 81 phase II‐III matches were identified including 252 trials. Mean (standard deviation) weighted difference (phase III minus II) was −4.2% (17.4) for ORR, 2.1 (6.7) months for PFS and −0.3 (5.1) months for OS, indicating very small average differences between phases. Differences varied substantially between individual indications: from −46.6% to 47.3% for ORR, from −5.3 to 35.9 months for PFS and from −13.3 to 10.8 months for OS. All covariates except blinding were associated with differences in effect sizes for at least 1 outcome.

Conclusions

The lack of marked average differences between phases may encourage decision‐makers to regard the quality of design and total body of evidence instead of differentiating between phases of clinical development. The large variability emphasizes that replication of study findings remains essential to confirm efficacy of oncology drugs and discern variables associated with demonstrated effects.

Evidence synthesis based on non-randomised studies-a critical review of studies leading to conclusions on fall risk properties of loop diuretics/beta-blockers

PURPOSE

To describe methodological and reporting issues in non-randomised comparative drug safety studies pooled in meta-analyses, with focus on confounding by indication.

METHODS

All studies included in statistically significant meta-analyses in a recent publication investigating fall risk properties of cardiovascular drugs were reviewed. Study characteristics were extracted and assessed.

RESULTS

Nine studies, including between 498 and 321,995 individuals, contributed data to the significant meta-analyses in which loop diuretics and beta-blockers were associated with falls, five published in 2015. Five individual studies reported a statistically significant association. In the five cohort studies, characteristics of exposed vs unexposed individuals were either not reported (n = 3) or differed substantially regarding morbidity (n = 2). Drug treatment was determined at baseline, and data on falls were collected for up to 2 years thereafter. Out of the four case-control studies, the cases and controls in only one study were matched for morbidity. Morbidity characteristics of fallers compared with non-fallers were either not reported (n = 2) or they differed (n = 1) or were reported according to the matched-for diseases (n = 1). Confounding by indication was explicitly discussed in two studies. None of the abstract conclusions considered causality issues or the possibility of confounding by indication.

CONCLUSIONS

Confounding by indication is a major issue in non-randomised comparative drug safety studies, a problem which may be concealed in meta-analyses. To enhance such research, compared groups need to be balanced regarding relevant factors including morbidities and characteristics adequately reported. Confounding by indication needs to be explicitly discussed and highlighted in the abstract conclusion.

Balancing early access with uncertainties in evidence for drugs authorized by prospective case series - systematic review of reimbursement decisions

Aims

To review clinical and cost‐effectiveness evidence underlying reimbursement decisions relating to drugs whose authorization mainly is based on evidence from prospective case series.

Methods

A systematic review of all new drugs evaluated in 2011–2016 within a health care profession‐driven resource prioritization process, with a market approval based on prospective case series, and a reimbursement decision by the Swedish Dental and Pharmaceutical Benefits Agency (TLV). Public assessment reports from the European Medicines Agency, published pivotal studies, and TLV, Scottish Medicines Consortium and National Institute of Health and Care Excellence decisions and guidance documents were reviewed.

Results

Six drug cases were assessed (brentuximab vedotin, bosutinib, ponatinib, idelalisib, vismodegib, ceritinib). The validity of the pivotal studies was hampered by the use of surrogate primary outcomes and the absence of recruitment information. To quantify drug treatment effect sizes, the reimbursement agencies primarily used data from another source in indirect comparisons. TLV granted reimbursement in five cases, compared with five in five cases for Scottish Medicines Consortium and four in five cases for National Institute of Health and Care Excellence. Decision modifiers, contributing to granted reimbursement despite hugely uncertain cost‐effectiveness ratios, were, for example, small population size, occasionally linked to budget impact, severity of disease, end of life and improved life expectancy.

Conclusion

For drugs whose authorization is based on prospective case series, most applications for reimbursement within public health care are granted. The underlying evidence has limitations over and above the design per se, and decision modifiers are frequently referred to in the value‐based pricing decision making.

Evaluating beneficial drug effects in a non-interventional setting: a review of effectiveness studies based on Swedish Prescribed Drug Register data

Aims

To describe and assess current effectiveness studies published up to 2014 using Swedish Prescribed Drug Register (SPDR) data.

Methods

Study characteristics were extracted. Each study was assessed concerning the clinical relevance of the research question, the risk of bias according to a structured checklist, and as to whether its findings contributed to new knowledge. The biases encountered and ways of handling these were retrieved.

Results

A total of 24 effectiveness studies were included in the review, the majority on cardiovascular or psychiatric disease (n = 17; 71%). The articles linked data from four (interquartile range: three to four) registers, and were published in 21 different journals with an impact factor ranging from 1.58 to 51.66. All articles had a clinically relevant research question. According to the systematic quality assessments, the overall risk of bias was low in one (4%), moderate in eight (33%) and high in 15 (62%) studies. Overall, two (8%) studies were assessed as contributing to new knowledge. Frequently occurring problems were selection bias making the comparison groups incomparable, treatment bias with suboptimal handling of drug exposure and an intention‐to‐treat approach, and assessment bias including immortal time bias. Good examples of how to handle bias problems included propensity score matching and sensitivity analyses.

Conclusion

Although this review illustrates that effectiveness studies based on dispensed drug register data can contribute to new evidence of intended effects of drug treatment in clinical practice, the expectations of such data to provide valuable information need to be tempered due to methodological issues.