RADIORYTHMIC: Phase III, Opened, Randomized Study of Postoperative Radiotherapy Versus Surveillance in Stage IIb/III of Masaoka Koga Thymoma after Complete Surgical Resection

INTRODUCTION

Thymomas are rare intrathoracic malignancies that may be aggressive and difficult to treat. Knowledge and level of evidence for treatment strategies are mainly based on retrospective studies or expert opinion. Currently there is no strong evidence that postoperative radiotherapy after complete resection of localized thymoma is associated with survival benefit in patients. RADIORYTHMIC is a phase III, randomized trial aiming at comparing postoperative radiotherapy versus surveillance after complete resection of Masaoka-Koga stage IIb/III thymoma. Systematic central pathologic review will be performed before patient enrollment as per the RYTHMIC network pathway.

PATIENTS AND METHODS

Three hundred fourteen patients will be included; randomization 1:1 will attribute either postoperative radiotherapy (50-54 Gy to the mediastinum using intensity-modulated radiation therapy or proton beam therapy) or surveillance. Stratification criteria include histologic grading (thymoma type A, AB, B1 vs B2, B3), stage, and delivery of preoperative chemotherapy. Patient recruitment will be mainly made through the French RYTHMIC network of 15 expert centers participating in a nationwide multidisciplinary tumor board. Follow-up will last 7 years. The primary endpoint is recurrence-free survival. Secondary objectives include overall survival, assessment of acute and late toxicities, and analysis of prognostic and predictive biomarkers.

RESULTS

The first patient will be enrolled in January 2021, with results expected in 2028.

[Short-term results of video-assisted lung cancer surgery in octogenarians]

INTRODUCTION

Due to an increase in life expectancy, onco-pulmonologists and thoracic surgeons are more frequently faced with octogenarian patients with lung cancer. In this age group, treatment modalities may need to be revised because of the increasing presence of comorbidities. Surgery remains the reference treatment for early stage disease, but mortality rates and postoperative complications are higher in this group of patients. One of the solutions to reduce the operative risk would be to develop videoassisted thoracoscopic pulmonary resection surgery. The aim of this study was to evaluate the results of this form of lung cancer surgery in octogenarians.

METHODS

All patients 80 years old or more who underwent videoassisted lung cancer surgery from 2014 to 2018 at Lyon University Hospital were included. Wedge resections and diagnostic procedures were excluded.

RESULTS

Nineteen patients (13 men, 6 women) were included. The median age was 82 years old. All patients had undergone videoassisted lobectomy. Three patients required conversion to thoracotomy (15.8%). All patients underwent complete resection (R0). One patient had N1 lymph node involvement, all others were N0. The postoperative complication rate was 68.4%, the majority of which were grade II of the Clavien classification. Perioperative mortality was 5.3%.

CONCLUSIONS

Videoassisted lung cancer resection in a selected population of octogenarians is associated with satisfactory short-term results. It is reasonable to favour minimally invasive techniques in this population, even if the proof of their superiority has not yet been firmly established.

P1255Comparative safety and effectiveness of standard doses of apixaban versus dabigatran, rivaroxaban, and VKAs in non-valvular atrial fibrillation patients in France: the NAXOS study

Background

Real-world data comparing all available oral anticoagulants (OAC) on a nationwide scale (i.e. in France: apixaban, rivaroxaban, dabigatran and vitamin K antagonists – VKAs) are lacking. In everyday practice, oral anticoagulants are often underdosed, which may render comparisons between agents difficult.

Purpose and methods

NAXOS is a French real-world study comparing the safety (major bleeding), effectiveness (stroke, systemic thromboembolic events (STE)) and all-cause mortality for apixaban, dabigatran, rivaroxaban, and VKAs, in adult patients with non-valvular atrial fibrillation (NVAF) initiating a given OAC between 2014 and 2016. The French national health insurance data (SNIIRAM) were used. Analyses were performed with adjustment on propensity scores. To avoid bias potentially related to underdosing, the present analysis included only patients receiving standard doses of apixaban (5mg bid), rivaroxaban (20mg od), and dabigatran (150 mg bid), or VKAs. Only OAC naïve patients were included.

Results

In the OAC-naive cohorts treated with apixaban, rivaroxaban, and dabigatran, 54,575 (62.3%), 65,208 (65.2%), and 9,000 (42.4%), respectively, had the standard dose at the index dispensation, and 112,628 patients received VKAs. After adjustment on propensity scores, apixaban 5 mg was associated with a lower risk of major bleeding, compared to VKAs (Hazard Ratio: 0.47; 95% CI: 0.43–0.51) and rivaroxaban 20mg (HR: 0.64; 0.59–0.71), but not to dabigatran 150 mg (HR: 0.97; 0.79–1.18). Apixaban was associated with a lower risk of stroke and STE, compared to VKAs (HR: 0.62; 0.56–0.69) but not to rivaroxaban (HR: 1.03; 0.92–1.16), and dabigatran (HR: 0.96; 0.76–1.21). Apixaban showed a lower risk of all-cause mortality compared to VKAs (HR: 0.44; 0.41–0.47) and rivaroxaban (HR: 0.87; 0.81–0.94) but not to dabigatran (HR: 1.10; 0.92–1.32).

Figure 1. Forest plot presenting the results of the standard dose analysis (PS adjusted).

Conclusions

The NAXOS population-based country-wide observational study shows that 42% to 65% of patients were treated with standard doses of OACs. Analyses of standard doses confirmed the superiority of apixaban compared with VKAs for the three studied outcomes and suggests better safety profile of apixaban compared to rivaroxaban but similar to dabigatran.

Acknowledgement/Funding

The Alliance Bristol-Myers Squibb/Pfizer

EvaluatioN of ApiXaban in strOke and systemic embolism prevention in patients with non-valvular atrial fibrillation in clinical practice Setting in France, rationale and design of the NAXOS: SNIIRAM study

Non-vitamin K antagonists oral anticoagulants (NOACs) have recently challenged vitamin-K antagonists (VKAs) for stroke and systemic embolism prophylaxis in patients with non-valvular atrial fibrillation (NVAF). Nevertheless, little information is available in routine clinical practice for France. The aim of this study is to describe the effectiveness and safety of apixaban, rivaroxaban, dabigatran or VKAs in routine clinical practice in adult NVAF patients for the prevention of stroke and systemic embolism in France. The NAXOS study is a nationwide observational retrospective cohort generated from the French national healthcare insurance database (SNIIRAM-a comprehensive in- and outpatient healthcare consumption database), consisting of eight distinct sub-cohorts of anticoagulant-naive or anticoagulant-experienced patients diagnosed with NVAF, newly initiated with either NOACs (dabigatran, rivaroxaban or apixaban) or VKAs. Patients will be included if initiating a new anticoagulant treatment for AF during the study period from 1 January 2014 to 31 December 2016. Primary effectiveness outcome will be the incidence of stroke or systemic thromboembolic events; primary safety outcome will be the incidence of major bleeding during the exposure period. The NAXOS study will provide routine clinical practice data on the effectiveness and safety profiles of apixaban vs other NOACs and VKAs in the prevention of stroke and systemic embolism in adult patients with NVAF in clinical practice conditions in France.

Changes in Persistent Asthma Care and Outcomes From 2006 to 2016 in France

BACKGROUND

Changes in asthma care need to be documented at arrival of biotherapies.

OBJECTIVES

To characterize changes in asthma care and outcomes in patients with persistent asthma.

METHODS

Repeated transversal analyses were conducted on a historical cohort using the French national claims data over 10 years. Patients aged 18 to 40 years with either 1 or more (any-use population) or 4 or more (high-use population) yearly dispensings of controller therapy were selected. Clinical and demographic features were characterized, and comparisons were made between 2006 and 2016 to assess temporal changes in asthma therapy, health care resource utilization, and outcomes.

RESULTS

In 2016, prevalent use of controller therapy was 5.2% (any-use population) and 0.8% (high-use population) of the population aged 18 to 40 years. In the any-use population, the use of long-acting β₂-agonists in monotherapy, and inhaled corticosteroids decreased (1.7% and 40.3% in 2016, respectively), whereas the use of fixed-dose combinations increased (56.4%). In both populations, visits to respiratory or hospital physicians and pulmonary function testing increased with time, in parallel to a decreasing number of general practitioner visits; in addition, oral corticosteroid use and incidence of emergency room visits increased. However, asthma hospitalizations and mortality remained low in both populations.

CONCLUSIONS

Changes in persistent asthma care included replacement of inhaled corticosteroids by fixed-dose combinations, decreased use of long-acting β₂-agonists as a monotherapy, and increased involvement of secondary care physicians. In parallel, despite low figures for hospital admissions and mortality, overall use of oral corticosteroids and incidence of emergency room visits have increased over the last decade.

Impact of bisphosphonate compliance on the risk of osteoporotic fracture in France

Limited information is available on the impact of bisphosphonate compliance levels on fracture risk in osteoporosis patients in France. The results of this nested case-control, retrospective study suggest that fracture risk did not significantly change with bisphosphonate compliance levels, except for highly compliant patients.

PURPOSE/INTRODUCTION

This was the first study conducted in France to evaluate the impact of compliance levels for bisphosphonates, the most frequently prescribed first-line anti-osteoporotic treatment, on fracture risk.

METHODS

This retrospective nested case-control study included patients ≥ 50 years old, who were recorded in a random sample of French claims data, did not die between 2006 and 2013, and received ≥ 1 reimbursement for anti-osteoporotic treatment between 2007 and 2013. Cases (patients hospitalised for osteoporosis-related fractures) were matched to 1-3 controls (patients hospitalised for other reasons). Patients hospitalised for fractures within 12 months preceding the first delivery of anti-osteoporotic treatment or during the first 24 months of follow-up were excluded. Bisphosphonate compliance during the 24 months preceding hospitalisation was calculated by the Continuous measure of Medication Acquisition version 7 (CMA7). We evaluated the impact of bisphosphonate compliance (CMA7 ≥ 80%) and very good compliance levels (CMA7 > 90%) on fracture risk.

RESULTS

In the main analysis, the mean CMA7 values during the 24 months preceding hospitalisation were 48.4% for the 434 cases and 51.3% for the 1123 age-matched controls. An adjusted conditional logistic regression showed no significant impact (odds ratio: 0.851 [95% confidence interval: 0.668, 1.084]) of bisphosphonate compliance on fracture occurrence. In the sensitivity analysis, including one randomly selected control per case and only controls with CMA7 values > 90%, occurrence of fractures was lower (odds ratio: 0.741 [95% confidence interval: 0.608, 0.903]) among the 119 controls.

CONCLUSION

In conclusion, this study suggested that very high levels of compliance with bisphosphonates are necessary to induce significant decreases in fracture risk.

Use of analgesics in France, following dextropropoxyphene withdrawal

Background

In 2009, the European Medicines Agency recommended withdrawal of dextropropoxyphene (DXP); in March 2011 it was withdrawn from the market in France. Up until that time the combination dextropropoxyphene-paracetamol (DXP/PC) was widely used for analgesia. At withdrawal, French regulators recommended that DXP/PC be replaced by other step 2 analgesics, i.e. tramadol, codeine, or opium-containing drugs, or by PC for a weak level of pain. To investigate prescribing behaviours after DXP/PC withdrawal, dispensations of analgesics before and after withdrawal were analysed.

Methods

Aggregated dispensation data of analgesics prescribed between January 2009 and December 2012 in the Rhône-Alpes region were obtained from the general health insurance claims data; changes in analgesic dispensation over time were analysed with the ATC/DDD methodology. Pre (Jan-June 2009) and post-withdrawal (Jan-June 2012) changes of DDDs where computed for each analgesic step.

Results

The dispensations of DXP/PC experienced a two-step decrease until 2011. Over the withdrawal period 2009-2012, there was a 14% decrease in the overall use of analgesic (from 109 to 94 DDDs), while the use of step 2 analgesics declined by 46% (− 22 DDDs, from 47 to 25 DDDs). This latter decline included a cessation of use of DXP/PC (29 DDDs in 2009) that were only in part (+ 7 DDDs, from 18 to 25 DDDs) compensated by increased use of codeine, tramadol and opium, in monotherapy or combined with PC. For step 1 analgesics, use increased with 9%, mostly PC (+ 8 DDDs, from 31 to 39 DDDs). Step 3 analgesics dispensations remained largely unchanged over this period (around 3 DDDs).

Conclusions

In the Rhône-Alpes region, DXP/PC withdrawal was accompanied in part by an increased use of same level analgesics, and in part by an increased use of PC in monotherapy. The extent of DXP/PC use before withdrawal, and the increased use of PC after DXP withdrawal, underline the complexity of pain management.

Long-Term Inhaled Corticosteroid Adherence in Asthma Patients with Short-Term Adherence

BACKGROUND

Although the use of inhaled corticosteroids (ICS) in asthma is known to be overall erratic, the long-term use of ICS by patients selected during an episode of regular use is poorly documented.

OBJECTIVE

In a cohort of patients with asthma regularly acquiring ICS therapy over several months, we verified whether these patients remained treated in the following 12 months. The correlates of regular ICS use over this period were investigated.

METHODS

A historical cohort of patients with asthma was identified from the Echantillon généraliste de bénéficiaires national French health care reimbursement data (2007-2012). Patients (6-40 years) were selected during a regular ICS use episode, with 3 or more ICS refills within 120 days. Continuous multiple-interval measures of medication availability (CMA) were computed for the 12 months after the third dispensation, and the factors associated with a CMA value of 80% or more (adherent patients) were identified.

RESULTS

Among 5096 patients (42.1% children/teenagers, 48.8% females), only 24.0% had a CMA value of 80% or more (mean CMA = 54.4%) over the 12 months following the ICS selection period. Achieving a CMA value of 80% or more was primarily associated with being a child/teenager (P = .002), having more severe or less controlled asthma (P = .007), more previous dispensing of short-acting beta agonists (P < .0001), and receiving devices with 200 unit doses (P < .0001). Adherent patients had more frequent general practitioner visits (P < .0001), more distinct prescribers of respiratory therapy (P = .0002), and more frequent switches of ICS (P < .0001).

CONCLUSIONS

Most patients with asthma selected during an episode of regular ICS use did not maintain therapy over the following months. Adherence should be repeatedly monitored, and the reasons for discontinuation should be investigated, at prescriber and patient levels.

Costs of perennial allergic rhinitis and allergic asthma increase with severity and poor disease control

BACKGROUND

Perennial allergic rhinitis (PAR) represents a global and public health problem, due to its prevalence, morbidity, and impact on the quality of life. PAR is frequently associated with allergic asthma (AA). Costs of PAR with or without AA are poorly documented.

OBJECTIVE

Our study aimed to detail medical resource utilization (MRU) and related direct cost for PAR, with or without concomitant AA, in France.

METHODS

Using Electronic Health Records (EHRs), we identified in 2010 two cohorts of PAR patients, based on General Practitioners' diagnoses and prescribing data, with and without concomitant AA. For each patient, the EHRs were linked to corresponding claims data with MRU and costs during years 2011 to 2013. Predefined subgroup analyses were performed according to severity of PAR and level of AA control.

RESULTS

The median annual cost reimbursed by social security system for a patient with PAR, and no AA was 159€ in 2013. This varied from 111€ to 188€ depending on PAR severity. For patients with PAR and concomitant AA, the median annual cost varied between 266€ and 375€, and drug treatment accounted for 42-55% of the costs, depending on asthma control.

CONCLUSION

This study linking diagnoses from EHRs to claims data collected valid information on PAR management, with or without concomitant AA, and on related costs. There was a clear increase in costs with severity of PAR and control of AA.

Anti-osteoporotic treatments in France: initiation, persistence and switches over 6 years of follow-up

Limited information is available on anti-osteoporotic treatment initiation patterns in France. In 2006-2013, the most frequently prescribed first-line treatment class for osteoporosis was represented by bisphosphonates (alendronic acid and risedronic acid), followed by strontium ranelate. Persistence with anti-osteoporotic treatment was low, with high proportions of treatment discontinuations and switches.

INTRODUCTION

This epidemiological, longitudinal study described first-line treatment initiation, persistence, switches to second-line treatment, and medical care consumption in osteoporotic patients in France during the 2007-2013 period.

METHODS

Patients aged ≥50 years, who were recorded in a French claims database and did not die during the observation period, were included if they met ≥1 inclusion criteria for osteoporosis in 2007 (≥1 reimbursement for anti-osteoporotic treatment, hospitalisation for osteoporotic fracture (spine, hip, femur, forearm bones, humerus, wrist), or ≥1 reimbursement for long-term osteoporosis-associated status). We collected data on consumption of anti-osteoporotic treatment (alendronic acid, ibandronic acid, risedronic acid, zoledronic acid, raloxifene, strontium ranelate, teriparatide) and of osteoporosis-related medical care after the date of first reimbursement for anti-osteoporotic treatment.

RESULTS

We obtained 2219 patients with a 6-year follow-up and 1387 who initiated an anti-osteoporotic treatment in 2007 and who can be selected for the treatment regimen analysis. The most frequently used first-line treatments were alendronic acid (32.7 %), risedronic acid (22.4 %), strontium ranelate (19.3 %), ibandronic acid (13.1 %) and raloxifene (12.2 %). Among patients who received these treatments, the highest persistence after 6 years was observed for raloxifene (37.3 %), alendronic acid (35.1 %) and risedronic acid (32.3 %). Treatment discontinuations were reported for 35.5 % (raloxifene) to 53.4 % (strontium ranelate) and treatment switches for 27.4 % (alendronic acid) to 56.6 % (ibandronic acid) of these patients.

CONCLUSIONS

This study showed that persistence with anti-osteoporotic treatment was relatively low in France, with high proportions of treatment discontinuations and switches, and that patients with osteoporosis were insufficiently monitored by bone specialists.

Level of Asthma Controller Therapy Before Admission to the Hospital

BACKGROUND

In asthma, choice of controller therapy and adherence to treatment can affect the risk of future severe exacerbations leading to hospitalization.

OBJECTIVE

Our objective was to characterize treatment dispensation profiles before hospital admission for asthma.

METHODS

Using a 1/97th random sample of the national French claims data, patients with asthma aged 6 to 40 years were identified between 2006 and 2014. Patients with subsequent asthma-related hospitalization were selected. On the basis of controller therapy dispensed in the 12 months before admission, treatment profiles were categorized into clusters, using Ward's minimum-variance hierarchical clustering method.

RESULTS

Of 17,846 patients with asthma, we identified 275 patients (1.5%) with an asthma-related hospitalization. Three distinct clusters were identified. The first cluster (63.6%) included patients with few dispensations of any controller medication (<1 unit). The second cluster (32.4%) consisted of patients with frequent dispensations of long-acting beta agonists (LABAs)/inhaled corticosteroids (ICS) in fixed-dose combinations. The third cluster (4%) comprised patients receiving free combinations of ICS and LABAs, with more dispensations of LABAs than of ICS.

CONCLUSIONS

In France, before an asthma-related hospitalization, more than 60% of patients received little controller therapy and 4% were exposed to higher dispensation of LABAs than of ICS. These results indicate that a large fraction of asthma-related hospitalizations can potentially be prevented with better pharmacotherapy.

What are the therapeutic alternatives to dextropropoxyphene in France? A prescribers' survey

About a year after dextropropoxyphene (DXP) withdrawal from the French market, we conducted a survey among members of the French Society of Anesthesia & Intensive Care Medicine (Sfar) and of the French Society of the Study and Treatment of Pain (SFETD) to identify the indications for which this WHO level II analgesic had been prescribed, the prescriber's feedback following withdrawal, and the substitutive analgesics prescribed. DXP had been prescribed by more than 75% of the 430 anaesthesiologists and 230 pain specialists interviewed, mainly for acute and chronic non-cancer pain of moderate intensity. While two thirds of pain specialists were not satisfied with DXP withdrawal, this decision did not affect the majority of anaesthesiologists. In both groups, the main substitutive analgesic was tramadol combined with acetaminophen, while only 24% of prescribers considered acetaminophen alone as a substitute.

Recurrent Wheezing in Infants: A Population-Based Study

Recurrent wheezing (RW) has a significant impact on infants, caregivers, and society, but morbidity and related medical resource utilization (MRU) have not been thoroughly explored. The burden of RW needs to be documented with population-based data. The objective was to assess the characteristics, medical management, and MRU of RW infants identified from national claims data. Infants aged from 6 to 24 months, receiving ≥2 dispensations of respiratory drugs within 3 months, and presenting a marker of poor control (index date), were selected. During the 6 months after index date, MRU was described in the cohort and among 3 subgroups with more severe RW, defined as ≥4 dispensations of respiratory drugs, ≥3 dispensations of oral corticosteroids (OCS), or ≥1 hospitalization for respiratory symptoms. A total of 115,489 infants had RW, corresponding to 8.2% of subjects in this age group. During follow-up, 68.7% of infants received inhaled corticosteroids, but only 1.8 U (unit) were dispensed over 6 months, suggesting discontinuous use. Control was mostly inadequate: 61.7% of subjects received OCS, 80.2% antibiotics, and 71.2% short-acting beta-agonists, and medical/paramedical visits were numerous, particularly for physiotherapy. Severe RW concerned 39.0% of the cohort; 32.8% and 11.7% of infants had repeated use of respiratory drugs and OCS, respectively, and 5.5% were hospitalized for respiratory symptoms. In this real-life nation-wide study, RW was common and infants had poor control and high MRU. Interventions are needed to support adequate use of controller therapy, and to improve medical care.

Influence of vectors' risk-spreading strategies and environmental stochasticity on the epidemiology and evolution of vector-borne diseases: the example of Chagas' disease

Insects are known to display strategies that spread the risk of encountering unfavorable conditions, thereby decreasing the extinction probability of genetic lineages in unpredictable environments. To what extent these strategies influence the epidemiology and evolution of vector-borne diseases in stochastic environments is largely unknown. In triatomines, the vectors of the parasite Trypanosoma cruzi, the etiological agent of Chagas’ disease, juvenile development time varies between individuals and such variation most likely decreases the extinction risk of vector populations in stochastic environments. We developed a simplified multi-stage vector-borne SI epidemiological model to investigate how vector risk-spreading strategies and environmental stochasticity influence the prevalence and evolution of a parasite. This model is based on available knowledge on triatomine biodemography, but its conceptual outcomes apply, to a certain extent, to other vector-borne diseases. Model comparisons between deterministic and stochastic settings led to the conclusion that environmental stochasticity, vector risk-spreading strategies (in particular an increase in the length and variability of development time) and their interaction have drastic consequences on vector population dynamics, disease prevalence, and the relative short-term evolution of parasite virulence. Our work shows that stochastic environments and associated risk-spreading strategies can increase the prevalence of vector-borne diseases and favor the invasion of more virulent parasite strains on relatively short evolutionary timescales. This study raises new questions and challenges in a context of increasingly unpredictable environmental variations as a result of global climate change and human interventions such as habitat destruction or vector control.

Adaptive developmental delay in Chagas disease vectors: an evolutionary ecology approach

Background

The developmental time of vector insects is important in population dynamics, evolutionary biology, epidemiology and in their responses to global climatic change. In the triatomines (Triatominae, Reduviidae), vectors of Chagas disease, evolutionary ecology concepts, which may allow for a better understanding of their biology, have not been applied. Despite delay in the molting in some individuals observed in triatomines, no effort was made to explain this variability.

Methodology

We applied four methods: (1) an e-mail survey sent to 30 researchers with experience in triatomines, (2) a statistical description of the developmental time of eleven triatomine species, (3) a relationship between development time pattern and climatic inter-annual variability, (4) a mathematical optimization model of evolution of developmental delay (diapause).

Principal Findings

85.6% of responses informed on prolonged developmental times in 5^th instar nymphs, with 20 species identified with remarkable developmental delays. The developmental time analysis showed some degree of bi-modal pattern of the development time of the 5^th instars in nine out of eleven species but no trend between development time pattern and climatic inter-annual variability was observed. Our optimization model predicts that the developmental delays could be due to an adaptive risk-spreading diapause strategy, only if survival throughout the diapause period and the probability of random occurrence of “bad” environmental conditions are sufficiently high.

Conclusions/Significance

Developmental delay may not be a simple non-adaptive phenotypic plasticity in development time, and could be a form of adaptive diapause associated to a physiological mechanism related to the postponement of the initiation of reproduction, as an adaptation to environmental stochasticity through a spreading of risk (bet-hedging) strategy. We identify a series of parameters that can be measured in the field and laboratory to test this hypothesis. The importance of these findings is discussed in terms of global climatic change and epidemiological consequences.

The developmental time of vector insects is important to their population dynamics, evolutionary biology, epidemiology of the diseases they transmit, and to their responses to global climatic change. In various triatomine species vectors of Chagas disease (Triatominae, Reduviidae), a delay in the molt of a small proportion of individuals has been observed, and from an evolutionary ecology approach, we propose the hypothesis that the developmental delay is an adaptation to environmental stochasticity through a spreading of risk (bet-hedging) diapause strategy. We confirmed, by means of a survey among specialists, the existence of the developmental delay in triatomines. Statistical descriptions of the developmental time of 11 species of triatomines showed some degree of bi-modality in nine of them. We predicted by means of an optimization model which genotype, coding for a given frequency of developmental diapause, is expected to evolve. We identified a series of parameters that can be measured in the field and in the laboratory to test the hypothesis of an optimal diapause frequency. We also discuss the importance of these findings for triatomines in terms of global climatic change and epidemiological consequences such as their resistance to insecticides.