Cost-effectiveness of alternative strategies for interferon-γ release assays and tuberculin skin test in tuberculous uveitis

Role of Interferon-Gamma Release Assay for the Diagnosis and Clinical Follow up in Ocular Tuberculosis

PURPOSE

To assess the performance of interferon-gamma release assay (IGRA) associated with tuberculosis skin test (TST) for ocular tuberculosis (OTB) diagnosis and therapeutic decision making.

METHOD

One hundred and ninety-one patients with ocular inflammation were prospectively followed-up. Patients with clinical signs highly suspected of OTB, TST≥10 mm, and/or IGRA≥0.35 IU/mL received antitubercular therapy (ATT). Sensitivity (Se), specificity (Sp), and area under the curve (AUC) were assessed.

RESULTS

Seventy-two (37.7%) patients received ATT for presumed OTB. Combining TST and IGRA had Se=89.6%, Sp=99.2%, and AUC (0.98) significantly higher compared to TST (0.85, Z=6.3, p<.001) or IGRA (0.95, Z=2.5, p=.01). Prior history of corticosteroids or immunosuppressant with concomitantly oral prednisone and baseline IGRA> 2.0 IU/mL was associated significantly with more recurrences in ATT patients (p=.01)      .

CONCLUSION

Considering TST and IGRA together was more effective in assessing OTB diagnosis. The real value of the IGRA test to predict recurrences needs further studies.

Interferon-gamma release assays in tuberculous uveitis: a comprehensive review

Tuberculous uveitis (TBU) comprises a broad clinical spectrum of ocular manifestations, making its diagnosis challenging. Ophthalmologists usually require evidence from investigations to confirm or support a clinical diagnosis of TBU. Since direct isolation of the causative organism from ocular specimens has limitations owing to the small volume of the ocular specimens, resultant test positivities are low in yield. Immunodiagnostic tests, including the tuberculin skin test and interferon-gamma release assays (IGRAs), can help support a clinical diagnosis of TBU. Unlike the tuberculin skin test, IGRAs are in vitro tests that require a single visit and are not affected by prior Bacillus Calmette-Guerin vaccination. Currently, available IGRAs consist of different techniques and interpretation methods. Moreover, newer generations have been developed to improve the sensitivity and ability to detect active tuberculosis. This narrative review collates salient practice points as a reference for general ophthalmologists, such as evidence for the utilization of IGRAs in patients with suspected TBU, and summarizes basic knowledge and details of clinical applications of these tests in a clinical setting.

Economic Analyses of Respiratory Tract Infection Diagnostics: A Systematic Review

BACKGROUND

Diagnostic testing for respiratory tract infections is a tool to manage the current COVID-19 pandemic, as well as the rising incidence of antimicrobial resistance. At the same time, new European regulations for market entry of in vitro diagnostics, in the form of the in vitro diagnostic regulation, may lead to more clinical evidence supporting health-economic analyses.

OBJECTIVE

The objective of this systematic review was to review the methods used in economic evaluations of applied diagnostic techniques, for all patients seeking care for infectious diseases of the respiratory tract (such as pneumonia, pulmonary tuberculosis, influenza, sinusitis, pharyngitis, sore throats and general respiratory tract infections).

METHODS

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, articles from three large databases of scientific literature were included (Scopus, Web of Science and PubMed) for the period January 2000 to May 2020.

RESULTS

A total of 70 economic analyses are included, most of which use decision tree modelling for diagnostic testing for respiratory tract infections in the community-care setting. Many studies do not incorporate a generally comparable clinical outcome in their cost-effectiveness analysis: fewer than half the studies (33/70) used generalisable outcomes such as quality-adjusted life-years. Other papers consider outcomes related to the accuracy of the test or outcomes related to the prescribed treatment. The time horizons of the studies generally are limited.

CONCLUSIONS

The methods to economically assess diagnostic tests for respiratory tract infections vary and would benefit from clear recommendations from policy makers on the assessed time horizon and outcomes used.

Uveitis: Autoimmunity… and beyond

OBJECTIVE

Uveitis is the most common ophthalmological finding in the practice of rheumatology and clinical immunology. The condition is frequently idiopathic but about 60 causes of uveitis have been described. Our aim was to analyze the clinical patterns and etiologies of uveitis in a tertiary referral center.

METHODS

The records of 912 consecutive patients referred to the department of internal medicine (Lyon University Hospital, Lyon, France) for the diagnostic work-up of uveitis were examined. Demographic, clinical, anatomical, and etiological features of uveitis were analyzed.

RESULTS

The mean age at onset was 48.8 years; 59.8% of the patients were women and 78.2% were Caucasians. Anterior uveitis was the most common type of uveitis (40.6%), followed by panuveitis (31.7%), posterior (18.75%) and intermediate uveitis (9%). 46.9% of the patients had idiopathic uveitis. The most common etiologies were systemic diseases (37.3%), such as sarcoidosis (17.1%), HLA-B27-related uveitis and/or spondyloarthritis (12.5%), and tuberculosis (7.5%).

CONCLUSION

We describe one of the largest cohorts of consecutive uveitis patients referred to a department of internal medicine. The high percentage of uveitis associated with underlying (systemic) diseases highlights the need for a multidisciplinary approach, in order to reduce the diagnostic delay.

A systematic review and economic evaluation of adalimumab and dexamethasone for treating non-infectious intermediate uveitis, posterior uveitis or panuveitis in adults

BACKGROUND

Non-infectious intermediate uveitis, posterior uveitis and panuveitis are a heterogeneous group of inflammatory eye disorders. Management includes local and systemic corticosteroids, immunosuppressants and biological drugs.

OBJECTIVES

To evaluate the clinical effectiveness and cost-effectiveness of subcutaneous adalimumab (Humira^®; AbbVie Ltd, Maidenhead, UK) and a dexamethasone intravitreal implant (Ozurdex^®; Allergan Ltd, Marlow, UK) in adults with non-infectious intermediate uveitis, posterior uveitis or panuveitis.

DATA SOURCES

Electronic databases and clinical trials registries including MEDLINE, EMBASE, Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effects and the World Health Organization's International Clinical Trials Registry Platform were searched to June 2016, with an update search carried out in October 2016.

REVIEW METHODS

Review methods followed published guidelines. A Markov model was developed to assess the cost-effectiveness of dexamethasone and adalimumab, each compared with current practice, from a NHS and Personal Social Services (PSS) perspective over a lifetime horizon, parameterised with published evidence. Costs and benefits were discounted at 3.5%. Substantial sensitivity analyses were undertaken.

RESULTS

Of the 134 full-text articles screened, three studies (four articles) were included in the clinical effectiveness review. Two randomised controlled trials (RCTs) [VISUAL I (active uveitis) and VISUAL II (inactive uveitis)] compared adalimumab with placebo, with limited standard care also provided in both arms. Time to treatment failure (reduced visual acuity, intraocular inflammation, new vascular lesions) was longer in the adalimumab group than in the placebo group, with a hazard ratio of 0.50 [95% confidence interval (CI) 0.36 to 0.70; p < 0.001] in the VISUAL I trial and 0.57 (95% CI 0.39 to 0.84; p = 0.004) in the VISUAL II trial. The adalimumab group showed a significantly greater improvement than the placebo group in the 25-item Visual Function Questionnaire (VFQ-25) composite score in the VISUAL I trial (mean difference 4.20; p = 0.010) but not the VISUAL II trial (mean difference 2.12; p = 0.16). Some systemic adverse effects occurred more frequently with adalimumab than with placebo. One RCT [HURON (active uveitis)] compared a single 0.7-mg dexamethasone implant against a sham procedure, with limited standard care also provided in both arms. Dexamethasone provided significant benefits over the sham procedure at 8 and 26 weeks in the percentage of patients with a vitreous haze score of zero (p < 0.014), the mean best corrected visual acuity improvement (p ≤ 0.002) and the percentage of patients with a ≥ 5-point improvement in VFQ-25 score (p < 0.05). Raised intraocular pressure and cataracts occurred more frequently with dexamethasone than with the sham procedure. The incremental cost-effectiveness ratio (ICER) for one dexamethasone implant in one eye for a combination of patients with unilateral and bilateral uveitis compared with limited current practice, as per the HURON trial, was estimated to be £19,509 per quality-adjusted life-year (QALY) gained. The ICER of adalimumab for patients with mainly bilateral uveitis compared with limited current practice, as per the VISUAL trials, was estimated to be £94,523 and £317,547 per QALY gained in active and inactive uveitis respectively. Sensitivity analyses suggested that the rate of blindness has the biggest impact on the model results. The interventions may be more cost-effective in populations in which there is a greater risk of blindness.

LIMITATIONS

The clinical trials did not fully reflect clinical practice. Thirteen additional studies of clinically relevant comparator treatments were identified; however, network meta-analysis was not feasible. The model results are highly uncertain because of the limited evidence base.

CONCLUSIONS

Two RCTs of systemic adalimumab and one RCT of a unilateral, single dexamethasone implant showed significant benefits over placebo or a sham procedure. The ICERs for adalimumab were estimated to be above generally accepted thresholds for cost-effectiveness. The cost-effectiveness of dexamethasone was estimated to fall below standard thresholds. However, there is substantial uncertainty around the model assumptions. In future work, primary research should compare dexamethasone and adalimumab with current treatments over the long term and in important subgroups and consider how short-term improvements relate to long-term effects on vision.

STUDY REGISTRATION

This study is registered as PROSPERO CRD42016041799.

FUNDING

The National Institute for Health Research Health Technology Assessment programme.

[Ocular tuberculosis]

Despite extensive investigations, including the use of Interferon-gamma release assays (IGRA), the diagnosis of intraocular tuberculosis (TB) remains challenging. Ocular evidence of Mycobacterium tuberculosis in low endemic countries for TB is extremely rare, leading mostly to a TB-related ocular inflammation presumptive diagnosis. This present work aims: to highlights the main clinical patterns suggestive of ocular TB; and the latest recommended guidelines for diagnosing ocular TB to clarify interferon-gamma release assay (IGRA) contribution and accuracy to the management of intraocular TB and its diagnosis, in addition to other available diagnostic tools, such as tuberculin skin test, bacteriologic and histologic analysis from intra/extra ocular sample and radiographic investigations; to define the accuracy of these diagnostic tools according to the endemic TB prevalence; and finally to identify therapeutic strategies adapted to the main clinical presentations of ocular TB. Our review of the literature shows that management of suspected ocular TB differs significantly based on whether patients are from high or low TB prevalence countries since accuracy of chest X-ray, tuberculin skin test and IGRA is significantly different. Taking into account these discrepancies, distinct guidelines should be determined for managing patients with suspected ocular TB, taking into consideration home prevalence of TB-patients.

Disparities in model-based cost-effectiveness analyses of tuberculosis diagnosis: A systematic review

Background

Structural approach disparities were minimally addressed in past systematic reviews of model-based cost-effectiveness analyses addressing Tuberculosis management strategies. This review aimed to identify the structural approach disparities in model-based cost-effectiveness analysis studies addressing Tuberculosis diagnosis and describe potential hazards caused by those disparities.

Methods

A systematic search to identify studies published before October 2015 was performed in five electronic databases. After removal of duplication, studies’ titles and abstracts were screened based on predetermined criteria. The full texts of potentially relevant studies were subsequently screened and excluded when they did not address active pulmonary Tuberculosis diagnosis. Quality of the studies was assessed using the “Philips’ checklist.” Various data regarding general information, cost-effectiveness results, and disease modeling were extracted using standardized data extraction forms. Data pertaining to models’ structural approaches were compared and analyzed qualitatively for their applicability in various study settings, as well as their potential influence on main outcomes and cost-effectiveness conclusion.

Results

A total of 27 studies were included in the review. Most studies utilized a static model, which could underestimate the cost-effectiveness of the diagnostic tools strategies, due to the omission of indirect diagnosis effects, i.e. transmission reduction. A few structural assumption disparities were found in the dynamic models. Extensive disparities were found in the static models, consisting of varying structural assumptions regarding treatment outcomes, clinical diagnosis and empirical treatment, inpatient discharge decision, and re-diagnosis of false negative patients.

Conclusion

In cost-effectiveness analysis studies addressing active pulmonary Tuberculosis diagnosis, models showed numerous disparities in their structural approaches. Several structural approaches could be inapplicable in certain settings. Furthermore, they could contribute to under- or overestimation of the cost-effectiveness of the diagnosis tools or strategies. They could thus lead to ambiguities and difficulties when interpreting a study result. A set of recommendations is proposed to manage issues related to these structural disparities.

Clinical Features and Prognostic Factors in Presumed Ocular Tuberculosis

PURPOSE

To characterize the clinical features in patients with presumed ocular tuberculosis (TB) and determine prognostic factors of visual outcomes and complications in this disease.

MATERIAL AND METHODS

Retrospective case series of 35 patients (29 females, 6 males) with presumed ocular TB from referral centers in Chile and Spain between 2002 and 2012. Medical records were reviewed, and data regarding clinical features, complications, best-corrected visual acuity (BCVA), duration of disease, extraocular manifestations, and therapy were retrieved. Prognostic factors for low vision (BCVA 20/50 or less), legal blindness (BCVA 20/200 or less), and complications (cataract, glaucoma, and macular lesion) were evaluated. To calculate correlations, we used Spearman's rank correlation test. To determine clinical predictors, we used the binary logistic regression test.

RESULTS

Anterior and non-granulomatous uveitis was the most common types of inflammation. Only 2 (5.7%) patients had respiratory symptoms, and 6 (17.1%) patients had an abnormal chest X-ray at diagnosis. All patients received combined antitubercular therapy with a mean duration of 6.9 ± 2.3 months. A longer duration of symptoms at diagnosis was associated with both low vision and legal blindness. Older patients had a higher risk of legal blindness. A longer duration of symptoms as well as anterior inflammation demonstrated an increased risk for cataract formation. The duration of the symptoms and baseline BCVA had a positive correlation with the final BCVA. Prognostic factors of macular lesions were not found.

CONCLUSIONS

The diagnosis of ocular TB can be difficult due to the lack of extraocular manifestations and the broad spectrum of ocular features. A longer duration of symptoms at diagnosis was associated with poorer visual outcomes and cataracts. Therefore, efforts should be made to avoid a delay in the diagnosis of ocular TB and to identify prognostic factors for visual outcomes and complications.

Diagnosis of Ocular Tuberculosis

Ocular tuberculosis remains a presumptive clinical diagnosis, as the gold standard tests for diagnosing ocular tuberculosis are often not useful: Mycobacterium tuberculosis cultures require weeks to process on Lowenstein-Jenson media and have low yield from ocular samples; while acid-fast bacilli smears or polymerase chain reaction detection of M. tuberculosis DNA have low sensitivities. Thus, diagnosis is often based on suggestive clinical signs, which are supported by positive investigations: tuberculin skin test or interferon-gamma release assays; chest X-ray findings suggestive of pulmonary tuberculosis, and/or evidence of associated systemic tuberculosis infections in the absence of other underlying disease. The aim of this review is to provide an update on the methods of diagnosing ocular tuberculosis, and discuss the challenges of its diagnosis. We also suggest a step-ladder approach to a more accurate diagnosis of ocular tuberculosis by combining the available diagnostic tests.