Treatments for giant cell arteritis: Meta-analysis and assessment of estimates reliability using the fragility index

Effect of combined treatment with prednisone and methotrexate versus prednisone alone over laboratory parameters in giant cell arteritis

OBJECTIVE

To compare the effect of combined treatment with prednisone and methotrexate (MTX) versus prednisone alone over laboratory parameters in giant cell arteritis (GCA).

PATIENTS AND METHODS

We performed a double-blind, placebo-controlled, randomized clinical trial about usefulness of treatment with prednisone and MTX versus prednisone and placebo in GCA (Ann Intern Med 2001;134:106-114). As a part of follow-up of patients (n=42), we performed laboratory analysis in 20 time points during the two-year period of follow-up. To analyze differences, we calculated the area under the curve (AUC) for erythrocyte sedimentation rate (ESR), hemoglobin, and platelets, and compared the results in both groups adjusting by time of follow-up, existence of relapses and dose of prednisone.

RESULTS

A total of 724 laboratory measurements were done. Median value of ESR was 33 [18-56] in patients with placebo and 26 [15-44] in patients with MTX (P=0.0002). No significant differences were observed in ESR during relapses. The mean ESR value followed a parallel course in both groups, but was lower in the group with MTX than in the group with placebo in 18 of 20 time points of follow-up. The AUC of ESR by time of follow-up was 28,461.7±12,326 in the group with placebo and 19,598.4±8,117 in the group with MTX (mean difference 8,863, 95% CI 1.542-16.184; P=0.019). The course of other laboratory parameters paralleled, without statistical significance, those observed for ESR.

CONCLUSIONS

These data, along with clinical data, suggest that MTX might play a role as a disease-modifying agent in the treatment of GCA.

Assessing the robustness of positive vascular surgery randomized controlled trials using their fragility index

OBJECTIVE

The fragility index (FI) measures the robustness of statistically significant findings in randomized controlled trials (RCTs) by quantifying the minimum number of event conversions required to reverse a dichotomous outcome's statistical significance. In vascular surgery, many clinical guidelines and critical decision-making points are informed by a handful of key RCTs, especially regarding open surgical versus endovascular treatment. The objective of this study is to evaluate the FI of RCTs with statistically significant primary outcomes that compared open vs endovascular surgery in vascular surgery.

METHODS

In this meta-epidemiological study and systematic review, MEDLINE, Embase, and CENTRAL were searched for RCTs comparing open versus endovascular treatments for abdominal aortic aneurysms, carotid artery stenosis, and peripheral arterial disease to December 2022. RCTs with statistically significant primary outcomes were included. Data screening and extraction were conducted in duplicate. The FI was calculated by adding an event to the group with the smaller number of events while subtracting a nonevent to the same group until Fisher's exact test produced a nonstatistically significant result. The primary outcome was the FI and proportion of outcomes where the loss to follow-up was greater than the FI. The secondary outcomes assessed the relationship of the FI to disease state, presence of commercial funding, and study design.

RESULTS

Overall, 5133 articles were captured in the initial search with 21 RCTs reporting 23 different primary outcomes being included in the final analysis. The median FI (first quartile, third quartile) was 3 (3, 20) with 16 outcomes (70%) reporting a loss to follow-up greater than its FI. Mann-Whitney U test revealed that commercially funded RCTs and composite outcomes had greater FIs (median, 20.0 [5.5, 24.5] vs median, 3.0 [2.0, 5.5], P = .035; median, 21 [8, 38] vs median, 3.0 [2.0, 8.5], P = .01, respectively). The FI did not vary between disease states (P = .285) or between index and follow-up trials (P = .147). There were significant correlations between the FI and P values (Pearson r = 0.90; 95% confidence interval, 0.77-0.96), and the number of events (r = 0.82; 95% confidence interval, 0.48-0.97).

CONCLUSIONS

A small number of event conversions (median, 3) are needed to alter the statistical significance of primary outcomes in vascular surgery RCTs evaluating open surgical and endovascular treatments. Most studies had loss to follow-up greater than its FI, which can call into question trial results, and commercially funded studies had a greater FI. The FI and these findings should be considered in future trial design in vascular surgery.

Thresholds for interpreting the fragility index derived from sample of randomised controlled trials in cardiology: a meta-epidemiologic study

The fragility index (FI) was proposed as a simplified way to communicate robustness of statistically significant results and their susceptibility to a change of a handful number of events. While this index is intuitive, it is not anchored by a cut-off or a guide for interpretation. We identified cardiovascular trials published in six high impact journals from 2007 to 2021 (500 or more participants and a dichotomous statistically significant primary outcome). We estimated area under curve (AUC) to determine FI value that best predicts whether the treatment effect was precise, defined as adequately powered for a plausible relative risk reduction (RRR) of 25% or 30% or having a CI that is sufficiently narrow to exclude a risk reduction that is too small (close to the null, <0.05). The median FI of 201 included cardiovascular trials was 13 (range 1-172). FI exceeded the number of patients lost to follow-up in 46/201 (22.89%) trials. FI values of 19 and 22 predicted that trials would be precise (powered for RRR of 30% and 25%; respectively, combined with CI that excluded risk reduction <0.05). AUC for meeting these precision criteria was 0.90 (0.86-0.94). In conclusion, FI values that range 19-22 may meet various definitions of precision and can be used as a rule of thumb to suggest that a treatment effect is likely precise and less susceptible to random error. The number of patients lost to follow-up should be presented alongside FI to better illustrate fragility.

Indirect Comparison of Glucocorticoid-Sparing Agents for Remission Maintenance in Giant Cell Arteritis: A Network Meta-analysis

OBJECTIVE

To compare and rank the effect of glucocorticoid-sparing agents in giant cell arteritis (GCA), for which several drugs have been evaluated but with a benefit-risk balance that remains uncertain.

METHODS

The MEDLINE and Clinical Trials databases were searched up to November 2021; all randomized controlled trials investigating glucocorticoids in GCA were included. The glucocorticoid regimen was dichotomized into short (≤6 months) or prolonged (>6 months) use. Risk of relapse and safety were estimated using network meta-analysis with frequentist random effects models.

RESULTS

Of the 96 records screened, 8 trials were included (572 patients). The trials compared glucocorticoids and a sparing agent: tocilizumab (2 trials), oral methotrexate (3 trials), infliximab (1 trial), etanercept (1 trial), and adalimumab (1 trial). The pooled prevalence of GCA relapse was 52.6% (95% CI, 38.1 to 66.9). The risk of relapse was significantly lower with tocilizumab compared with methotrexate (relative risk [RR], 0.41; 95% CI, 0.17 to 0.97) and prolonged (RR, 0.41; 95% CI, 0.20 to 0.83) and short (RR, 0.32; 95% CI, 0.16 to 0.66) glucocorticoid use. The risk of relapse was not significantly different with methotrexate compared with short (RR, 0.79; 95% CI, 0.48 to 1.31) and prolonged (RR, 0.95; 95% CI, 0.31 to 2.89) glucocorticoid use. The frequency of serious adverse events and serious infection was comparable between the different drugs. The certainty of the evidence was low to very low.

CONCLUSION

This meta-analysis suggests that tocilizumab may be superior to other sparing agents to prevent GCA relapse, but with a low to very low certainty of evidence, and that safety is comparable to the other drugs.

REGISTRATION

The protocol of the meta-analysis is registered in the international prospective register of systematic reviews PROSPERO (https://www.crd.york.ac.uk/prospero/; registration CRD42020112387).

Intravenous tocilizumab for the treatment of giant cell arteritis: a phase Ib dose-ranging pharmacokinetic bridging study

Background

Subcutaneous tocilizumab (TCZ SC) is approved globally for giant cell arteritis (GCA). This phase Ib study investigated the pharmacokinetics, pharmacodynamics, safety, and exploratory efficacy of intravenous (IV) TCZ 6 and 7 mg/kg in patients with GCA. This study explored an IV dose resulting in a minimum exposure level within the range of effective trough concentrations achieved with TCZ SC dosing in GCA and not exceeding the exposure of the well-tolerated 8 mg/kg IV every 4 weeks (Q4W) in rheumatoid arthritis (RA).

Methods

Patients with GCA who had received ≥ 5 doses of TCZ IV 8 mg/kg Q4W and achieved remission were enrolled. Patients received 5 doses of TCZ IV 7 mg/kg Q4W in period 1 and, if still in remission, 5 doses of 6 mg/kg Q4W in period 2. Pharmacokinetic endpoints were maximum concentration (C_max), minimum concentration (C_trough), area under the curve over a dosing interval (AUC_τ), and mean concentration (C_mean) of TCZ after the last dose of each period. Other endpoints included pharmacodynamic markers, safety, and exploratory efficacy.

Results

In 24 patients, the median (range) age was 65.5 (57–90) years, and 62.5% were female. TCZ exposures (C_max and AUC_τ) were 11.2% and 20.0% lower at the 6- than 7-mg/kg dose. The mean interleukin 6 (IL-6) serum concentrations were elevated at baseline and remained elevated, with slightly higher concentrations in period 1 than in period 2. The mean serum soluble IL-6 receptor concentrations were elevated at baseline and comparable between the 2 doses at steady state. C-reactive protein levels and most erythrocyte sedimentation rates were within normal ranges throughout the study. Overall, 22 patients (91.7%) had ≥ 1 adverse event, and 4 (16.7%) had a serious adverse event. No patients experienced a GCA flare, and all remained in remission throughout the study.

Conclusions

Both doses of TCZ IV Q4W were generally well tolerated in patients with GCA. The C_max and C_mean achieved with 6 mg/kg IV Q4W in patients with GCA were similar to those in patients with RA treated with 8 mg/kg IV Q4W, and C_trough was within the range observed in patients with GCA treated with SC dosing every week or every 2 weeks.

Trial registration

ClinicalTrials.gov, NCT03923738

Tocilizumab for giant cell arteritis

BACKGROUND

Giant cell arteritis (GCA) is the most common form of systemic vasculitis in people older than 50 years of age. It causes granulomatous inflammation of medium- to large-sized vessels. Tocilizumab is a recombinant monoclonal antibody directed against interleukin-6 receptors (IL-6R).

OBJECTIVES

To assess the effectiveness and safety of tocilizumab, given alone or with corticosteroids, compared with therapy without tocilizumab for treatment of GCA.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2020, Issue 1); Ovid MEDLINE; Embase.com; PubMed; Latin American and Caribbean Health Science Information database (LILACS); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). There were no date or language restrictions in the electronic search for trials. We last searched the electronic databases on 3 January 2020.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) that compared tocilizumab of any dosage regimen (alone or with corticosteroids) with therapy without tocilizumab that had a minimum follow-up of six months. Participants were at least 50 years of age, with biopsy-proven GCA or by large-vessel vasculitis by angiography, and met the American College of Rheumatology 1990 guidelines for GCA.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology.

MAIN RESULTS

Main results We included two RCTs in the review. The studies were conducted in the USA, Canada, and Europe and enrolled a total of 281 participants with GCA, of whom 74% were women. The mean age of participants was 70 years, with new-onset or relapsing GCA, and fulfilled the 1990 American College of Rheumatology criteria with no uncontrolled comorbidities. Both studies were funded by F. Hoffmann-La Roche AG, the manufacturer of tocilizumab. Findings One RCT (30 participants) compared tocilizumab administered every four weeks versus placebo. Point estimates at 12 months and beyond favored tocilizumab over placebo in terms of sustained remission (risk ratio (RR) 4.25, 95% confidence interval (CI) 1.21 to 14.88; moderate-certainty evidence). Point estimates suggest no evidence of a difference for all-cause mortality at 12 months or more (RR 0.17, 95% CI 0.01 to 3.94; moderate-certainty evidence). At 12 months, mean time to first relapse after induction of remission was 25 weeks in favor of participants receiving tocilizumab compared to placebo (mean difference (MD) 25, 95% CI 11.4 to 38.6; moderate-certainty evidence). The second RCT (250 participants) randomized participants into two intervention and two comparator groups to receive tocilizumab weekly (100 participants), bi-weekly (49 participants), weekly placebo + 26-week taper (50 participants), or weekly placebo + 52-week taper (51 participants). At 12 months, point estimates from this study on proportion of participants with sustained remission favored participants who received tocilizumab weekly versus placebo + 52-week taper (RR 3.17, 95% CI 1.71 to 5.89; 151 participants); tocilizumab weekly versus placebo + 26-week taper (RR 4.00, 95% CI 1.97 to 8.12; 150 participants); tocilizumab every other week versus placebo + 52-week taper (RR 3.01, 95% CI 1.57 to 5.75; 100 participants); tocilizumab every other week versus placebo + 26-week taper (RR 3.79, 95% CI 1.82 to 7.91; 99 participants) (moderate-certainty evidence). Point estimates on proportion of participants who did not need escape therapy (defined by the study as the inability to keep to the protocol-defined prednisone taper) favored participants who received tocilizumab weekly versus placebo + 52-week taper (RR 1.71, 95% CI 1.24 to 2.35; 151 participants); tocilizumab weekly versus placebo + 26-week taper (RR 2.96, 95% CI 1.83 to 4.78; 150 participants); tocilizumab every other week versus placebo + 52-week taper (RR 1.49, 95% CI 1.04 to 2.14; 100 participants) but not tocilizumab every other week versus placebo + 26-week taper (RR 0.65, 95% CI 0.27 to 1.54; 99 participants) (moderate-certainty evidence). This study did not report mean time to first relapse after induction of remission or all-cause mortality.  Across comparison groups, the same study found no evidence of a difference  in vision changes and inconsistent evidence with regard to quality of life. Evidence on quality of life as assessed by the physical (MD 8.17, 95% CI 4.44 to 11.90) and mental (MD 5.61, 95% CI 0.06 to 11.16) component score of the 36-Item Short Form Health Survey (SF-36) favored weekly tocilizumab versus placebo + 52-week taper but not bi-weekly tocillizumab versus placebo + 26-week taper (moderate-certainty evidence). Adverse events One RCT reported a lower percentage of participants who experienced serious adverse events when receiving tocilizumab every four weeks versus placebo. The second RCT reported no evidence of a difference among groups with regard to adverse events; however, fewer participants reported serious adverse events in the tocilizumab weekly and tocilizumab biweekly interventions compared with the placebo + 26-week taper and placebo + 52-week taper comparators. Investigators in both studies reported that infection was the most frequently reported adverse event.

AUTHORS' CONCLUSIONS

This review indicates that tocilizumab therapy may be beneficial in terms of proportion of participants with sustained remission, relapse-free survival, and the need for escape therapy. While the evidence was of moderate certainty, only two studies were included in the review, suggesting that further research is required to corroborate these findings. Future trials should address issues related to the required duration of therapy, patient-reported outcomes such as quality of life and economic outcomes, as well as the clinical outcomes evaluated in this review.

Advances in the Treatment of Giant Cell Arteritis

Giant cell arteritis (GCA) is the most common vasculitis among elderly people. The clinical spectrum of the disease is heterogeneous, with a classic/cranial phenotype, and another extracranial or large vessel phenotype as the two more characteristic patterns. Permanent visual loss is the main short-term complication. Glucocorticoids (GC) remain the cornerstone of treatment. However, the percentage of relapses with GC alone is high, and the rate of adverse events affects more than 80% of patients, so it is necessary to have alternative therapeutic options, especially in patients with worse prognostic factors or high comorbidity. MTX is the only DMARD that has shown to reduce the cumulative dose of GC, while tocilizumab is the first biologic agent approved due to its ability to decrease the relapse rate and lower the cumulative GC doses. However, apart from the IL-6 pathway, there are other pro-inflammatory cytokines and growth factors involved in the typical intima hyperplasia and vascular remodeling of GCA. Among them, the more promising targets in GCA treatment are the IL12/IL23 axis antagonists, IL17 inhibitors, modulators of T lymphocytes, and inhibitors of either the JAK/STAT pathway, the granulocyte-macrophage colony-stimulating factor, or the endothelin, all of which are updated in this review.

Tocilizumab for giant cell arteritis

BACKGROUND

Giant cell arteritis (GCA) is the most common form of systemic vasculitis in people older than 50 years of age. It causes granulomatous inflammation of medium- to large-sized vessels. Tocilizumab is a recombinant monoclonal antibody directed against interleukin-6 receptors (IL-6R).

OBJECTIVES

To assess the effectiveness and safety of tocilizumab, given alone or with corticosteroids, compared with therapy without tocilizumab for treatment of GCA.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (which contains the Cochrane Eyes and Vision Trials Register) (2020, Issue 1); Ovid MEDLINE; Embase.com; PubMed; Latin American and Caribbean Health Science Information database (LILACS); ClinicalTrials.gov; and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP). There were no date or language restrictions in the electronic search for trials. We last searched the electronic databases on 3 January 2020.

SELECTION CRITERIA

We included only randomized controlled trials (RCTs) that compared tocilizumab of any dosage regimen (alone or with corticosteroids) with therapy without tocilizumab that had a minimum follow-up of six months. Participants were at least 50 years of age, with biopsy-proven GCA or by large-vessel vasculitis by angiography, and met the American College of Rheumatology 1990 guidelines for GCA.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methodology.

MAIN RESULTS

Main results We included two RCTs in the review. The studies were conducted in the USA, Canada, and Europe and enrolled a total of 281 participants with GCA, of whom 74% were women. The mean age of participants was 70 years, with new-onset or relapsing GCA, and fulfilled the 1990 American College of Rheumatology criteria with no uncontrolled comorbidities. Both studies were funded by F. Hoffmann-La Roche AG, the manufacturer of tocilizumab. Findings One RCT (30 participants) compared tocilizumab administered every four weeks versus placebo. Point estimates at 12 months and beyond favored tocilizumab over placebo in terms of sustained remission (risk ratio (RR) 4.25, 95% confidence interval (CI) 1.21 to 14.88; moderate-certainty evidence). Point estimates suggest no evidence of a difference for all-cause mortality at 12 months or more (RR 0.17, 95% CI 0.01 to 3.94; moderate-certainty evidence). At 12 months, mean time to first relapse after induction of remission was 25 weeks in favor of participants receiving tocilizumab compared to placebo (mean difference (MD) 25, 95% CI 11.4 to 38.6; moderate-certainty evidence). The second RCT (251 participants) randomized participants into two intervention and two comparator groups to receive tocilizumab weekly (100 participants), bi-weekly (49 participants), weekly placebo + 26-week taper (50 participants), or weekly placebo + 52-week taper (51 participants). At 12 months, point estimates from this study on proportion of participants with sustained remission favored participants who received tocilizumab weekly versus placebo + 52-week taper (RR 3.17, 95% CI 1.71 to 5.89; 151 participants); tocilizumab weekly versus placebo + 26-week taper (RR 4.00, 95% CI 1.97 to 8.12; 150 participants); tocilizumab every other week versus placebo + 52-week taper (RR 3.01, 95% CI 1.57 to 5.75; 100 participants); tocilizumab every other week versus placebo + 26-week taper (RR 3.79, 95% CI 1.82 to 7.91; 99 participants) (moderate-certainty evidence). Point estimates on proportion of participants who did not need escape therapy (defined by the study as the inability to keep to the protocol-defined prednisone taper) favored participants who received tocilizumab weekly versus placebo + 52-week taper (RR 1.71, 95% CI 1.24 to 2.35; 151 participants); tocilizumab weekly versus placebo + 26-week taper (RR 2.96, 95% CI 1.83 to 4.78; 150 participants); tocilizumab every other week versus placebo + 52-week taper (RR 1.49, 95% CI 1.04 to 2.14; 100 participants); tocilizumab every other week versus placebo + 26-week taper (RR 0.65, 95% CI 0.27 to 1.54; 99 participants) (moderate-certainty evidence). This study did not report mean time to first relapse after induction of remission or all-cause mortality. The same study found no evidence of a difference between groups with regard to vision changes and quality of life, except for the assessment of quality of life with the physical component score of the 36-Item Short Form Health Survey (SF-36), which favored weekly tocilizumab versus placebo + 52-week taper (MD 8.17, 95% CI 4.44 to 11.90; moderate-certainty evidence). Adverse events One RCT reported a lower percentage of participants who experienced serious adverse events when receiving tocilizumab every four weeks versus placebo. The second RCT reported no evidence of a difference among groups with regard to adverse events; however, fewer participants reported serious adverse events in the tocilizumab weekly and tocilizumab biweekly interventions compared with the placebo + 26-week taper and placebo + 52-week taper comparators. Investigators in both studies reported that infection was the most frequently reported adverse event.

AUTHORS' CONCLUSIONS

This review indicates that tocilizumab therapy may be beneficial in terms of proportion of participants with sustained remission, relapse-free survival, and the need for escape therapy. While the evidence was of moderate certainty, only two studies were included in the review, suggesting that further research is required to corroborate these findings. Future trials should address issues related to the required duration of therapy, patient-reported outcomes such as quality of life and economic outcomes, as well as the clinical outcomes evaluated in this review.

Frequent fragility of randomized controlled trials for HCC treatment

Background

The fragility index (FI) of trial results can provide a measure of confidence in the positive effects reported in randomized controlled trials (RCTs). The aim of this study was to calculate the FI of RCTs supporting HCC treatments.

Methods

A methodological systematic review of RCTs in HCC treatments was conducted. Two-arm studies with randomized and positive results for a time-to-event outcome were eligible for the FI calculation.

Results

A total of 6 trails were included in this analysis. The median FI was 0.5 (IQR 0–10). FI was ≤7 in 4 (66.7%) of 6 trials; in those trials the fragility quotient was ≤1%.

Conclusion

Many phase 3 RCTs supporting HCC treatments have a low FI, which challenges the confidence in concluding the superiority of these drugs over control treatments.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-021-08133-8.

Giant cell arteritis: A nationwide, population-based cohort study on incidence, diagnostic imaging, and glucocorticoid treatment

AIM

The study investigated the development over time of the incidence, diagnostic imaging, and treatment of giant cell arteritis (GCA).

METHOD

This nationwide, population-based cohort study was conducted in Denmark using medical and administrative registries. Incident GCA cases from 1996-2018 were defined as patients aged ≥50 years registered with a first-time GCA diagnosis and ≥3 prescriptions for glucocorticoids (GCs) within 6 months after diagnosis. We determined incidence rates of GCA, the proportion of patients still receiving GCs >2 years after diagnosis, the proportion of patients receiving temporal artery biopsies (TAB) and diagnostic imaging including ultrasound, positron emission tomography, magnetic resonance, and/or computed tomography angiography at the time of diagnosis.

RESULTS

We identified 9908 incident GCA cases. The incidence rates of GCA remained stable at 19-25 per 100,000 people aged >50 years from 1996-2018. The proportion of GCA patients receiving a TAB remained constant until 2016, after which it promptly declined from 70-80% to 29-39%. In contrast, the proportion of patients receiving diagnostic imaging increased from 2% to 66% from 2000-2018. The proportion of GCA patients remaining in GC treatment has steadily decreased from 1996-2016, but remains high at 64%, 40%, and 34% after 2, 5, and 10 years following the diagnosis, respectively. The cumulative GC dose has remained relatively stable.

CONCLUSION

Incidence rates of GCA have remained stable since 1996 despite increasing use of diagnostic imaging. There is a clear discrepancy between current international GCA treatment guidelines and the clinical practice up to 2018.

Evaluation of the fragility of pivotal trials used to support US Food and Drug Administration approval for plaque psoriasis

BACKGROUND

Over the last 5 years, there has been a rapid growth in the number of clinical trials used to support a US Food and Drug Administration (FDA) approval for systemic therapies with labeled indications for plaque psoriasis.

OBJECTIVE

We aim to evaluate the fragility of clinical trial data used to support FDA approval of therapies for psoriasis.

METHODS

We reviewed the primary endpoints of the pivotal trials of all systemic medications with a labeled indication for plaque psoriasis available from Drugs@FDA.

RESULTS

Sixty-nine clinical trial primary endpoints met inclusion criteria and were assessed for robustness, yielding a median fragility index of 72 and a median fragility quotient of 0.19.

LIMITATIONS

Efficacy and statistical analysis data for several approved medications were not available on the product label or on Drugs@FDA.

CONCLUSIONS

When compared with randomized controlled trials for FDA approval across various diseases, pivotal trials in psoriasis appear quite robust to changes in outcomes.

Fragility Index in Cardiovascular Randomized Controlled Trials

BACKGROUND

Efficacy of an intervention is commonly evaluated using P values, in addition to effect size measures such as absolute risk reduction, relative risk reduction, and numbers needed to treat. However, these measures are not always intuitive to clinicians. The fragility index (FI) is a more intuitive number that can facilitate interpretation but can only be used with binary outcomes. FI is the minimum number of patients who must be moved from the nonevent group to the event group to turn a significant result nonsignificant. In this retrospective analysis, we assessed the robustness of cardiovascular randomized controlled trials (RCTs), which report a positive (statistically significant) primary outcome by using the FI.

METHODS AND RESULTS

We searched Medline from 2007 to 2017 to identify cardiovascular RCTs published in 6 high impact journals (The Lancet, New England Journal of Medicine, Journal of the American Medical Association, Circulation, Journal of the American College of Cardiology and European Heart Journal). Only RCTs with sample sizes >500 and a 2-by-2 factorial design or dichotomous primary outcomes were selected. FI was calculated using a defined approach. Among the cohort of 123 RCTs that met inclusion criteria, median FI was 13 (interquartile range, 5-26). In 28 trials (22.8%), FI ranged between 1 and 4. In 37 trials (30.1%), number of patients lost to follow-up was higher than the FI. Pharmaceutical interventions had higher FI compared with other interventions, FI=19 (7-52; P=0.002). Median FI varied according to subspecialty (electrophysiology=2; heart failure=11; interventional cardiology=8; P=0.020) and multiregional RCTs had higher FI=22 (12-53.25; P=0.023). FI did not differ based on risk of bias indicators, funding, or publication year.

CONCLUSIONS

Considerable variations in FI were observed among cardiovascular trials, suggesting the need for careful interpretation of results, particularly when number of patients lost to follow-up exceeds FI.

Data linkage analysis of giant cell arteritis in Italy: Healthcare burden and cost of illness in the Italian region of Friuli Venezia Giulia (2001-2017)

Giant cell arteritis (GCA) is the most common vasculitis in adults. However, comprehensive analyses of the healthcare burden are still scarce. The aim of the study is to report the healthcare burden and cost of illness of GCA in the Friuli Venezia Giulia (FVG) region of Italy, based on a data linkage analysis. To this end, a retrospective study was conducted through the integration of many administrative health databases of the FVG region as the source of information. Cases were identified from two verified, partially overlapping sources (the rare disease registry and medical exemption database). From 2001 to 2017, 208 patients with GCA were registered. The prevalence of GCA in the population aged ⩾ 45 years as of December 31, 2017 was 27.2/100,000 inhabitants (95% CI 23.5-31.4). The mean time of observation was 4.5 ± 3.6 years. A total of 3182 visits (338 per 100 patient-years) was recorded. The most frequent specialty visits were rheumatology (n = 610, 19.2%), followed by internal medicine (n = 564, 17.7%). A total of 287 hospitalizations (30 per 100 patient-years) were reported. A total of 13,043 prescriptions (1386 per 100 patient-years) were registered. More than half of the patients were prescribed an immunosuppressive agent. The overall estimated direct healthcare cost was €2,234,070, corresponding to €2374 per patient-year. Overall, GCA is a rare disease which implies a high healthcare cost.

The Fragility of Statistically Significant Findings in Pediatric Critical Care Randomized Controlled Trials

OBJECTIVES

The Fragility Index measures the number of events on which the statistical significance of a result depends and has been suggested as an adjunct statistical assessment for interpretation of trial results. This study aimed to assess the robustness of statistically significant results from pediatric critical care randomized controlled trials with dichotomous outcomes.

DATA SOURCES

A previously published scoping review of pediatric critical care randomized controlled trials (www.PICUtrials.net).

STUDY SELECTION

A total of 342 trials were screened for inclusion. After applying inclusion/exclusion criteria, 43 fulfilled eligibility criteria and were included in the analysis.

DATA EXTRACTION

Calculation of Fragility Index for trials reporting a statistically significant dichotomous outcome, and analysis of the relationship between trial characteristics and Fragility Index.

DATA SYNTHESIS

The median Fragility Index was 2 (interquartile range, 1-6). The median sample size was 98 (interquartile range, 50-148) and sample size demonstrated a strong correlation with the Fragility Index (r = 0.729; n = 43; p < 0.001). The median number of outcome events was 8 (interquartile range, 4-15) and the total number of outcome events also showed a strong correlation with the Fragility Index (r = 0.728; n = 43; p < 0.001).

CONCLUSIONS

Results from pediatric critical care randomized controlled trials with dichotomous outcomes reporting statistically significant findings often hinge on a small number of outcome events. Clinicians should exercise caution when interpreting results of trials with a low Fragility Index.