Habitually wearing high heels may improve user walking economy in any footwear.

The habitual use of high-heeled footwear may structurally remodel user leg muscle tendons, thereby altering their functional capabilities. High heels set users' ankles in relatively plantarflexed positions, causing calf muscle tendons to operate at relatively short lengths. Habitually operating muscle tendons at relatively short lengths induces structural remodeling that theoretically affects muscle metabolism. Because structural changes occur within the body, the user's locomotor metabolism may change in any footwear condition (e.g., conventional shoes, barefoot). Here, we studied the influence of habitual high-heel use on users' leg muscle-tendon structure and metabolism during walking in flat-soled footwear. We tested eight participants before and after 14 wk of agreeing to wear high heels as their daily shoes. Overall, participants who wore high heels >1,500 steps per day, experienced a 9% decrease in their net metabolic power during walking in flat-soled footwear (d = 1.66, P ≤ 0.049), whereas participants who took <1,000 daily steps in high heels did not (d = 0.44; P = 0.524). Across participants, for every 1,000 daily steps in high heels, net metabolic power during walking in flat-soled footwear decreased 5.3% (r = -0.73; P = 0.040). Metabolic findings were partially explained (r2 = 0.43; P = 0.478) by trending shorter medial gastrocnemius fascicle lengths (d = 0.500, P = 0.327) and increased Achilles tendon stiffness (d = 2.889, P = 0.088). The high-heel intervention did not alter user walking stride kinematics in flat-soled footwear (d ≤ 0.567, P ≥ 0.387). While our limited dataset is unable to establish the mechanisms underlying the high-heel-induced walking economy improvement, it appears that prescribing specific footwear use can be implemented to alter user muscle-tendon properties and augment their function in any shoes.NEW & NOTEWORTHY Habitually wearing high-heeled footwear structurally remodels leg muscle tendons and improves user walking economy, regardless of worn attire.

Reduced Achilles tendon stiffness in aging persists at matched activations and associates with higher metabolic cost of walking.

The mechanisms responsible for increased walking metabolic cost among older adults are poorly understood. We recently proposed a theoretical premise by which age-related reductions in Achilles tendon stiffness (k AT ) can disrupt the neuromechanics of calf muscle behavior and contribute to faster rates of oxygen consumption during walking. The purpose of this study was to objectively evaluate this premise. We quantified k AT at a range of matched activations prescribed using electromyographic biofeedback and walking metabolic cost in a group of 15 younger (age: 23±4 yrs) and 15 older adults (age: 72±5 yrs). Older adults averaged 44% less k AT than younger adults at matched triceps surae activations (p=0.046). This effect appeared to arise not only from altered tendon length-tension relations with age, but also from differences in the operating region of those length-tension relations between younger and older adults. Older adults also walked with a 17% higher net metabolic power than younger adults (p=0.017). In addition, we discovered empirical evidence that lesser k AT exacts a metabolic penalty and was positively correlated with higher net metabolic power during walking (r=-0.365, p=0.048). These results pave the way for interventions focused on restoring ankle muscle-tendon unit structural stiffness to improve walking energetics in aging.

Shorter muscle fascicle operating lengths increase the metabolic cost of cyclic force production.

During locomotion, force-producing limb muscles are predominantly responsible for an animal's whole body metabolic energy expenditure. Animals can change the length of their force-producing muscle fascicles by altering body posture (e.g., joint angles), the structural properties of their biological tissues over time (e.g., tendon stiffness), or the body's kinetics (e.g., body weight). Currently, it is uncertain whether relative muscle fascicle operating lengths have a measurable effect on the metabolic energy expended during cyclic locomotion-like contractions. To address this uncertainty, we quantified the metabolic energy expenditure of human participants, as they cyclically produced two distinct ankle moments at three ankle angles (90°, 105°, and 120°) on a fixed-position dynamometer using their soleus. Overall, increasing participant ankle angle from 90° to 120° (more plantar flexion) reduced minimum soleus fascicle length by 17% (both moment levels, P < 0.001) and increased metabolic energy expenditure by an average of 208% across both moment levels (both P < 0.001). For both moment levels, the increased metabolic energy expenditure was not related to greater fascicle positive mechanical work (higher moment level, P = 0.591), fascicle force rate (both P ≥ 0.235), or model-estimated active muscle volume (both P ≥ 0.122). Alternatively, metabolic energy expenditure correlated with average relative soleus fascicle length (r = -0.72, P = 0.002) and activation (r = 0.51, P < 0.001). Therefore, increasing active muscle fascicle operating lengths may reduce metabolic energy expended during locomotion.NEW & NOTEWORTHY During locomotion, active muscles undergo cyclic length-changing contractions. In this study, we isolated confounding variables and revealed that cyclically producing force at relatively shorter fascicle lengths increases metabolic energy expenditure. Therefore, muscle fascicle operating lengths likely have a measurable effect on the metabolic energy expenditure during locomotion.

Disease burden in people with cystic fibrosis heterozygous for F508del and a minimal function mutation.

BACKGROUND: People with cystic fibrosis (CF) heterozygous for F508del-CFTR and a minimal function CFTR mutation (F/MF) that results in no CFTR protein or results in CFTR protein that is not responsive to tezacaftor, ivacaftor, and tezacaftor/ivacaftor in vitro comprise a sizeable percentage of the US CF population. This retrospective, cross-sectional, observational study aimed to characterize CF burden in this subpopulation. METHODS: People ≥2 years of age in the US CF Foundation Patient Registry with a CF diagnosis, F/MF genotype, and ≥1 encounters in 2017 were included. Descriptive analyses assessed lung function, nutritional parameters, microbiology, hospitalization and pulmonary exacerbation rates, and CF-related complications. Results were stratified by age group; select characteristics were summarized by percent predicted FEV1 (ppFEV1) and ethnicity. RESULTS: 5348 people met inclusion criteria. Rates of positive bacterial cultures, pulmonary exacerbations, and hospitalizations were generally higher in older age groups. Prevalence of prescribed symptomatic CF therapies was substantial and also generally higher in older age groups. ppFEV1 was lower in older age groups. A greater percentage of adolescents and adults reported complications, including cirrhosis, osteoporosis, osteopenia, and sinus disease, than younger age groups. Increased prevalence of cultured Pseudomonas aeruginosa and prescribed chronic therapy was seen with decreasing ppFEV1. In each age group, ppFEV1 was slightly higher in the non-Hispanic cohort than in the Hispanic cohort. CONCLUSIONS: People with F/MF genotypes have substantial disease burden that worsened in older age groups consistent with the progressive nature of CF, indicating need for additional treatment options in this subpopulation.

Trajectories of the Transition Readiness Assessment Questionnaire Among Youth With Inflammatory Bowel Disease.

OBJECTIVE: The objective of this study was to describe in detail the trends of the Transition Readiness Assessment Questionnaire (TRAQ-20) with respect to patient age and gender among a cohort of 655 youth with inflammatory bowel disease (IBD) to enhance the tool's utility in clinical and research settings. MATERIALS AND METHODS: All participants in the Crohn's and Colitis Foundation's IBD Partners and IBD Partners Kids and Teens Cohorts ages 12 to 21 who completed the TRAQ-20 at least once were included. We computed centile scores for the TRAQ-20 and applied Kernel regression to generate curves. We computed mean scores for each TRAQ-20 domain by age for the overall cohort and stratified by gender. RESULTS: TRAQ-20 scores generally increase with age. Males have a steeper trajectory from ages 17 to 19 compared with females. By age 21, median overall TRAQ-20 scores for women and men were 4.4 and 4.7, respectively. The "Talking with Providers" domain of the TRAQ-20 had high scores throughout the age range of the cohort, while others had lower scores in younger ages and higher scores in older ages. All TRAQ-20 domains had mean scores of 4 or greater (out of a possible 5) among 21-year-olds. CONCLUSIONS: TRAQ-20 scores increase with age. The rate of increase varies by gender. Rates of increase also differ across domains. The use of transition readiness growth curves can help providers and researchers identify patients who are not achieving expected levels of transition readiness and determine the level of transition readiness that a patient much achieve before transfer to adult care.

Financial impacts of the COVID-19 pandemic on cystic fibrosis care: lessons for the future.

BACKGROUND: Chronic care delivery models faced unprecedented financial pressures, with a reduction of in-person visits and adoption of telehealth during the COVID-19 pandemic. We sought to understand the reported financial impact of pandemic-related changes to the cystic fibrosis (CF) care model. METHODS: The U.S. CF Foundation State of Care surveys fielded in Summer 2020 (SoC1) and Spring 2021 (SoC2) included questions for CF programs on the impact of pandemic-related restrictions on overall finances, staffing, licensure, and reimbursement of telehealth services. Descriptive analyses were conducted based on program type. RESULTS: Among the 286 respondents (128 pediatric, 118 adult, 40 affiliate), the majority (62%) reported a detrimental financial impact to their CF care program in SoC1, though fewer (42%) reported detrimental impacts in SoC2. The most common reported impacts in SoC1 were redeployment of clinical staff (68%), furloughs (52%), hiring freezes (51%), decreases in salaries (34%), or layoffs (10%). Reports of lower reimbursement for telehealth increased from 30% to 40% from SoC1 to SoC2. Projecting towards the future, only a minority (17%) of program directors in SoC2 felt that financial support would remain below pre-pandemic levels. CONCLUSIONS: The COVID-19 pandemic resulted in financial strain on the CF care model, including challenges with reimbursement for telehealth services and reductions in staffing due to institutional changes. Planning for the future of CF care model needs to address these short-term impacts, particularly to ensure a lack of interruption in high-quality multi-disciplinary care.

Patient and family experience of telehealth care delivery as part of the CF chronic care model early in the COVID-19 pandemic.

BACKGROUND: During the COVID-19 pandemic, CF centers shifted to a telehealth delivery model. Our study aimed to determine how people with CF (PwCF) and their families experienced telehealth and assessed its quality and acceptability for future CF care. METHODS: The CF Patient and Family State of Care Survey (PFSoC) was fielded from August 31-October 30, 2020. The PFSoC explored themes of overall telehealth quality, ease of use, desirability, and preference for a future mix of in-person and telehealth care. Demographic covariates considered included: gender, age, CFTR modulator status, and region of residence. RESULTS: 424 PwCF and parents of PwCF responded (47% parents). Most (81%) reported a telehealth visit which included a MD/APP and nurse team members. 91% found telehealth easy to use, and 66% reported similar/higher quality than in-person care. One-third (34%) reported the highest desire for future telehealth care, with 45% (n =212) desiring 50% or more of visits conducted via telehealth. Adults were more likely than parents to report highest desire for future telehealth (64% vs. 36%). Respondents who perceived telehealth as similar/higher quality were more likely to desire future telehealth compared to those who perceived telehealth as lower quality (96% vs. 50%). Mixed methods analysis revealed themes affecting perceptions of telehealth. CONCLUSIONS: PwCF desire for future telehealth was influenced by perception of quality and age. Several themes emerged that need to be explored as telehealth is adapted into the CF chronic care model, especially when thinking about integration into pediatric care.

Evaluating barriers to and promoters of telehealth during the COVID-19 pandemic at U.S. cystic fibrosis programs.

BACKGROUND: Cystic fibrosis (CF) care programs in the United States rapidly adopted telehealth during the COVID-19 pandemic. Understanding factors that promote or impede telehealth will inform planning for future telehealth-enabled care models. METHODS: Adult, pediatric, and affiliate CF care programs in the United States (n = 287) were surveyed twice eight months apart in 2020-2021 about telehealth use. Programs were asked to describe barriers to and promoters of telehealth. RESULTS: Ninety-seven percent of programs provided telehealth services. In the first CF Care Program State of Care Survey (SoC1), programs estimated that 57% of patients exclusively received in-person care, 36% of patients received telehealth by phone/computer with video, and 8% of patients received telephone-only care. In the second CF Care Program State of Care Survey (SoC2), programs estimated that 80% of visits were in-person and 15% were via audio and video telehealth. Pediatric programs (21%) were less likely than adult (37%) or affiliate (41%) programs to recommend telehealth (p = 0.007). All programs ranked lack of internet access as the highest barrier to patient engagement with telehealth. Promoters of telehealth were increased accessibility and avoidance of infection transmission. Top ranked changes to improve telehealth were expanded provision of remote monitoring devices and technology access. Similar proportions of program types anticipated institutional telehealth expansion. CONCLUSION: During the COVID-19 pandemic, CF programs in the United States identified factors to improve future care delivery via telehealth. Targeting specific barriers and promoters will improve the use and quality of telehealth throughout the care center network.

Remote monitoring in telehealth care delivery across the U.S. cystic fibrosis care network.

BACKGROUND: Cystic fibrosis (CF) programs and people with CF (PwCF) employed various monitoring methods for virtual care during the COVID-19 pandemic. This paper characterizes experiences with remote monitoring across the U.S. CF community. METHODS: The CF Foundation (CFF) sponsored distribution of home spirometers (April 2020 to May 2021), surveys to PwCF and CF programs (July to September 2020), and a second program survey (April to May 2021). We used mixed methods to explore access, use, and perspectives regarding the use of remote monitoring in future care. RESULTS: By October 2020, 13,345 spirometers had been distributed, and 19,271 spirometers by May 2021. Programs (n=286) estimated proportions of PwCF with home devices increased over seven months: spirometers (30% to 70%), scales (50% to 70%), oximeters (5% to 10%) with higher estimates in adult programs for spirometers and oximeters. PwCF (n=378) had access to scales (89%), followed by oximeters (48%) and spirometers (47%), often using scales and oximeters weekly, and spirometers monthly. Over both surveys, some programs had no method to collect respiratory specimens for cultures associated with telehealth visits (47%, n=132; 41%, n=118). Most programs (81%) had a process for phlebotomy associated with a telehealth visit, primarily through off-site labs. Both PwCF and programs felt future care should advance remote monitoring and recommended improvements for access, training, and data collection systems. CONCLUSIONS: PwCF and programs experienced unprecedented access to remote monitoring and raised its importance for future care. Improvements to current systems may leverage these shared experiences to augment future care models.

Transition Readiness Not Associated With Measures of Health in Youth With IBD.

BACKGROUND: It remains unclear how transition readiness is associated with various domains of health in children and young adults. Our objective was to describe the transition readiness of children and young adults with inflammatory bowel disease (IBD) and examine its associations with demographic factors, IBD activity, and measures of physical, psychological, and social health. METHODS: We recruited children ages 12 to 17 and young adults ages 18 to 20 from 2 internet-based cohorts sponsored by the Crohn's & Colitis Foundation. Participants self-reported demographics, IBD activity, transition readiness, health-related quality of life, and Patient-Reported Outcomes Information Systems domains of physical, psychological, and social health. RESULTS: Among 361 pediatric and 119 adult participants, age and female sex were associated with transition readiness. The association was greater in the pediatric cohort. Having IBD in remission was associated with worse transition readiness in the pediatric cohort only (beta = 0.3; P = 0.003). Health-related quality of life and Patient-Reported Outcomes Information Systems measures of fatigue, pain interference, and sleep disturbance were not associated with transition readiness in either children or adults. We observed few small associations between psychological or social health and transition readiness. Better transition readiness was associated with greater anxiety in adults (beta = -0.02; P = 0.02) and greater peer relationships among children (beta = 0.01; P = 0.009). CONCLUSIONS: In children and young adults with IBD, transition readiness was associated with older age and female sex. Associations between transition readiness and physical, psychological, and social health were either small, inconsistent across age groups, or nonexistent.

Adding carbon fiber to shoe soles may not improve running economy: a muscle-level explanation.

In an attempt to improve their distance-running performance, many athletes race with carbon fiber plates embedded in their shoe soles. Accordingly, we sought to establish whether, and if so how, adding carbon fiber plates to shoes soles reduces athlete aerobic energy expenditure during running (improves running economy). We tested 15 athletes as they ran at 3.5 m/s in four footwear conditions that varied in shoe sole bending stiffness, modified by carbon fiber plates. For each condition, we quantified athlete aerobic energy expenditure and performed biomechanical analyses, which included the use of ultrasonography to examine soleus muscle dynamics in vivo. Overall, increased footwear bending stiffness lengthened ground contact time (p = 0.048), but did not affect ankle (p ≥ 0.060), knee (p ≥ 0.128), or hip (p ≥ 0.076) joint angles or moments. Additionally, increased footwear bending stiffness did not affect muscle activity (all seven measured leg muscles (p ≥ 0.146)), soleus active muscle volume (p = 0.538; d = 0.241), or aerobic power (p = 0.458; d = 0.04) during running. Hence, footwear bending stiffness does not appear to alter the volume of aerobic energy consuming muscle in the soleus, or any other leg muscle, during running. Therefore, adding carbon fiber plates to shoe soles slightly alters whole-body and calf muscle biomechanics but may not improve running economy.

Survey of patients with cystic fibrosis and caregivers decisions regarding CFTR modulators.

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators are a novel approach to CF management that has become more readily available chronic CF therapies for certain populations of patients with CF. A cross-sectional survey of adults with CF and caregivers of pediatric patients with CF was done in two CF Centers to better understand the decision-making process including the potential influence of social media, CF care-teams, and family members on their decision whether to begin a CFTR modulator. For the 90 participants, the most common influences in the decision to start modulator therapy were the CF providers/care teams (n = 63), parents (n = 49), and individuals with CF (n = 27). The most impactful influence in the decision-making process were providers/care team (n = 47) and parents (n = 18). Social media was an influence for only 12 respondents, with an overall positive impact. Information from the CF Foundation was an influence for 12 participants and the main influence for six participants. The most common reasons for stopping lumacaftor-ivacaftor were having tezacaftor-ivacaftor as an option (n = 25) and side-effects (n = 15). Family and CF clinicians were the two main influences on the decision to initiate modulator therapy. CF clinicians were seen to be the most influential source. Social media had less influence on the decision-making process than expected despite the wide presence of the CF community online.

The exoskeleton expansion: improving walking and running economy.

Since the early 2000s, researchers have been trying to develop lower-limb exoskeletons that augment human mobility by reducing the metabolic cost of walking and running versus without a device. In 2013, researchers finally broke this 'metabolic cost barrier'. We analyzed the literature through December 2019, and identified 23 studies that demonstrate exoskeleton designs that improved human walking and running economy beyond capable without a device. Here, we reviewed these studies and highlighted key innovations and techniques that enabled these devices to surpass the metabolic cost barrier and steadily improve user walking and running economy from 2013 to nearly 2020. These studies include, physiologically-informed targeting of lower-limb joints; use of off-board actuators to rapidly prototype exoskeleton controllers; mechatronic designs of both active and passive systems; and a renewed focus on human-exoskeleton interface design. Lastly, we highlight emerging trends that we anticipate will further augment wearable-device performance and pose the next grand challenges facing exoskeleton technology for augmenting human mobility.

Exoskeletons Improve Locomotion Economy by Reducing Active Muscle Volume.

Exoskeletons that improve locomotion economy typically are engineered to reduce users' limb joint mechanical work or moments. Yet, limb joint dynamics do not necessarily reflect muscle dynamics, which dictate whole-body metabolic energy expenditure. Here, we hypothesize that exoskeletons primarily reduce user metabolic energy expenditure across locomotion conditions by reducing active muscle volume.

Linkage of the CF foundation patient registry with the pediatric health information system database.

INTRODUCTION: The Cystic Fibrosis Foundation Patient Registry (CFFPR) contains clinical and demographic data from ∼85% of US cystic fibrosis (CF) patients across 120 care centers, but lacks robust inpatient hospitalization data. In contrast, the Pediatric Health Information System (PHIS) database includes inpatient clinical and resource utilization data from 49 US children's hospitals. The creation of a linked CFFPR-PHIS dataset can uniquely address questions related to in-hospital pediatric CF treatment and management. We assessed the feasibility of linking the CFFPR and PHIS databases and determined if successfully linked CF patients were generalizable to unlinked patients. METHODS: CF patients ≤21 years were eligible for linkage. The CFFPR and PHIS databases were linked at the patient level using indirect identifiers in a stepwise, deterministic, linkage approach. A validation cohort was created using a subset of patients to determine linkage accuracy. Clinical and demographic characteristics between linked and unlinked patients were compared to determine generalizability of the linked cohort. RESULTS: Of the 11 735 CF patients eligible for linkage from January 1st, 2005 through December 31st, 2016, 10 660 (91%) were successfully linked. Results of our single center validation cohort illustrated 100% accuracy. When compared to unlinked CF patients, fewer linked patients were born before 1990, more were Hispanic, and more were from West-affiliated PHIS hospitals. Otherwise, no clinically meaningful differences were seen between linked and unlinked CF patients. CONCLUSIONS: We demonstrated successful linkage of the CFFPR and PHIS databases, and created a large generalizable pediatric CF cohort for use in CF-related research.

Interprofessional provider educational needs and preferences regarding the provision of sexual and reproductive health care in cystic fibrosis.

BACKGROUND: Sexual and reproductive health (SRH) is an important disease-specific concern for adolescent and young adult (AYA) women that is not consistently addressed in cystic fibrosis (CF) centers. This study identifies educational needs and preferences of interprofessional CF providers regarding SRH in AYA women with CF. METHODS: Interprofessional CF providers participated in an anonymous survey regarding general and CF-specific SRH knowledge and skills, factors for optimizing SRH care, and preferred approaches for SRH training. We calculated descriptive statistics for all respondents and stratified by provider type. RESULTS: A total of 523 providers completed the survey (39% physicians/advanced practice providers, 19% nurses, 20% social workers, and 22% other disciplines). Half reported comfort responding to female AYA SRH concerns; however, only one-third were comfortable asking appropriate questions and confident taking a sexual history. Only 29% were comfortable with their current CF-specific SRH knowledge. Respondents' preferred SRH topics for further training included: pregnancy/parenthood planning, sexual functioning, urinary incontinence, intimate partner violence, and taking a sexual history. Nearly two-thirds felt having connection to women's health specialists familiar with CF would facilitate SRH care. Approximately one-third desired SRH educational materials for providers to view at point-of-care or through online case-based learning; <10% were interested in role playing SRH skills. CONCLUSION: Many interprofessional CF providers lack comfort and skills in addressing SRH with AYA women with CF. Provider training needs and approaches identified in this study can be used to develop tailored educational interventions to improve comprehensive CF care.

Social support is associated with fewer reported symptoms and decreased treatment burden in adults with cystic fibrosis.

BACKGROUND: Although social support has been linked to a variety of health outcomes in those with and without chronic illness, this construct has rarely been studied in adults with cystic fibrosis (CF), who may face a unique set of clinical and psychosocial barriers. The current study explored the relationships between social support, mental health, physical health, treatment activity, and disease-specific quality of life in a sample of adults with CF. METHODS: Participants in the study included 250 adults with CF who took part in a larger longitudinal study. Participants were administered a battery of measures including a social support evaluation (Interpersonal Support Evaluation List, ISEL), a health assessment (Memorial Symptom Assessment Scale, MSAS), a health-related quality of life measure (Cystic Fibrosis Questionnaire - Revised, CFQ-R), and treatment activity questionnaires (Tool for Adherence Behaviour Screening, TABS and other surveys). RESULTS: Linear regression analyses indicated that greater social support was associated with fewer self-reported mental and physical health symptoms, digestive symptoms, and eating disturbances over time. Social support also was associated with elevated emotional, social, and role functioning as well as vitality and improved body image. Those who reported more support perceived less treatment burden and better overall perceptions of their health. CONCLUSIONS: Social support has been shown to be associated with health outcomes in other chronic illnesses, and the same is true for adults with CF. This study fills gaps in the literature by examining outcomes of social support in this emerging adult population and providing a potential area for intervention.

Healthcare expenditures for privately insured US patients with cystic fibrosis, 2010-2016.

OBJECTIVES: Published cost estimates for cystic fibrosis (CF) are based on older data and do not reflect increased use of specialty drugs in recent years. We assessed recent trends in healthcare expenditures for CF patients in the United States (US) with employer-sponsored health insurance. METHODS: The study is a retrospective analysis of claims data for privately insured individuals aged 0-64 years who were continuously enrolled in non-capitated plans for at least 1 calendar year during 2010-2016. Mean annual expenditures during a calendar year were calculated for individuals who met a claims-based CF case definition. Average annual growth rates were calculated through linear regression of the natural logarithm of annual expenditures. RESULTS: The annual CF prevalence was 1.1-1.4 per 10 000 adults and 2.9-3.0 per 10 000 children. Average spending adjusted for inflation nearly doubled from roughly $67 000 per patient in 2010 and 2011 to approximately $131 000 per patient in 2016. Inflation-adjusted spending on outpatient and inpatient care increased by 0.5% and 2.5% per year, respectively, whereas pharmaceutical spending increased by 20.2% per year. Virtually all of the growth in pharmaceutical spending was accounted for by spending on specialty drugs; inflation-adjusted spending on other medications increased by 1.3% per year. The annual growth rate in pharmaceutical spending rose by 33.1% during 2014-2016, the years during which lumacaftor/ivacaftor was introduced. CONCLUSIONS: Per-patient expenditures for privately-insured patients with CF almost doubled during 2010-2016; specialty drugs were largely responsible for this increase, with a major contribution from new, genotype-targeted CFTR modulator medications.

Rate and predictors of prescription of lumacaftor - Ivacaftor in the 18 months following approval in the United States.

RATIONALE: Lumacaftor-ivacaftor (LUM-IVA) was approved in the US in 2015 for patients with CF aged >12 homozygous for the delF508 mutation, and patients aged 6 to 12 in 2016. OBJECTIVES: To examine the rate of initial LUM-IVA prescriptions following approval. METHODS: We compared patients eligible for LUM-IVA in the CF Foundation Patient Registry with and without prescriptions in 2015-2016. RESULTS: 5534 (53%) eligible patients had reported prescriptions. Prescription rate in children ages 6-11 was 19% and 61% among patients ≥12 years old. Individuals ≥12 with prescriptions more likely observed among those with private insurance, clinical trial participation, ages 18-30, FEV1 < 90%, more pulmonary exacerbations, and more use of chronic medications. CONCLUSIONS: LUM-IVA uptake was less rapid than what was previously observed for ivacaftor, a CFTR modulator approved for a different population. Age, insurance status, disease severity and use of other therapies differed in those prescribed LUM-IVA in the initial post-approval period.