All Publications

  • Activity data from wearables as an indicator of functional capacity in patients with cardiovascular disease. PloS one Rens, N. n., Gandhi, N. n., Mak, J. n., Paul, J. n., Bent, D. n., Liu, S. n., Savage, D. n., Nielsen-Bowles, H. n., Triggs, D. n., Ata, G. n., Talgo, J. n., Gutierrez, S. n., Aalami, O. n. 2021; 16 (3): e0247834


    Smartphone and wearable-based activity data provide an opportunity to remotely monitor functional capacity in patients. In this study, we assessed the ability of a home-based 6-minute walk test (6MWT) as well as passively collected activity data to supplement or even replace the in-clinic 6MWTs in patients with cardiovascular disease.We enrolled 110 participants who were scheduled for vascular or cardiac procedures. Each participant was supplied with an iPhone and an Apple Watch running the VascTrac research app and was followed for 6 months. Supervised 6MWTs were performed during clinic visits at scheduled intervals. Weekly at-home 6MWTs were performed via the VascTrac app. The app passively collected activity data such as daily step counts. Logistic regression with forward feature selection was used to assess at-home 6MWT and passive data as predictors for "frailty" as measured by the gold-standard supervised 6MWT. Frailty was defined as walking <300m on an in-clinic 6MWT.Under a supervised in-clinic setting, the smartphone and Apple Watch with the VascTrac app were able to accurately assess 'frailty' with sensitivity of 90% and specificity of 85%. Outside the clinic in an unsupervised setting, the home-based 6MWT is 83% sensitive and 60% specific in assessing "frailty." Passive data collected at home were nearly as accurate at predicting frailty on a clinic-based 6MWT as was a home-based 6MWT, with area under curve (AUC) of 0.643 and 0.704, respectively.In this longitudinal observational study, passive activity data acquired by an iPhone and Apple Watch were an accurate predictor of in-clinic 6MWT performance. This finding suggests that frailty and functional capacity could be monitored and evaluated remotely in patients with cardiovascular disease, enabling safer and higher resolution monitoring of patients.

    View details for DOI 10.1371/journal.pone.0247834

    View details for PubMedID 33760846

  • Reliability and Repeatability of a Smartphone-Based 6-Minute Walk Test as a Patient-Centered Outcome Measure European Heart Journal - Digital Health, Mak, J., Rens, N., et al 2021

    View details for DOI 10.1093/ehjdh/ztab018

  • A Distributed Registry: Smartphone-Connected Database Driven by Patient-Reported Outcomes Triggs, D., Rens, N., Savage, D. M., Nielsen-Bowles, H., Talgo, J. C., Mak, J. J., Gutierrez, S., Aalami, O. MOSBY-ELSEVIER. 2020: E259
  • Cost-Effectiveness of a Pharmacogenomic Test for Stratified Isoniazid Dosing in Treatment of Active Tuberculosis. Clinical infectious diseases : an official publication of the Infectious Diseases Society of America Rens, N. E., Uyl-de Groot, C. A., Goldhaber-Fiebert, J. D., Croda, J. n., Andrews, J. R. 2020


    There is marked interindividual variability in metabolism and resulting toxicity and effectiveness of drugs used for tuberculosis treatment. For isoniazid, mutations in the N-acetyltransferase-2 (NAT2) gene explain over 88% of pharmacokinetic variability. However, weight-based dosing remains the norm globally. The potential clinical impact and cost-effectiveness of pharmacogenomic-guided therapy (PGT) is unknown.We constructed a decision tree model to project lifetime costs and benefits of isoniazid PGT for drug-susceptible tuberculosis in Brazil, South Africa, and India. PGT was modeled to reduce isoniazid toxicity among slow NAT2 acetylators and reduce treatment failure among rapid acetylators. The genotyping test was assumed to cost the same as the GeneXpert test. The main outcomes were costs (2018 USD), quality adjusted life years (QALYs), and incremental cost-effectiveness ratios.In Brazil, PGT gained 19 discounted life years (23 QALYs) and cost $11,064 per 1,000 patients, a value of $476 per QALY gained. In South Africa, PGT gained 15 life years (19 QALYs) and cost $33,182 per 1,000 patients, a value of $1,780 per QALY gained. In India, PGT gained 20 life years (24 QALYs) and cost $13,195 per 1,000 patients, a value of $546 per QALY gained. One-way sensitivity analyses showed the cost-effectiveness to be robust to all input parameters. Probabilistic sensitivity analyses were below per capita GDP in all three countries in 99% of simulations.Isoniazid PGT improves health outcomes and would be cost-effective in the treatment of drug-susceptible tuberculosis in Brazil, South Africa, and India.

    View details for DOI 10.1093/cid/ciz1212

    View details for PubMedID 31905381

  • National assessment of availability, awareness, and utilization of supervised exercise therapy for peripheral artery disease patients with intermittent claudication. Journal of vascular surgery Dua, A., Gologorsky, R., Savage, D., Rens, N., Gandhi, N., Brooke, B., Corriere, M., Jackson, E., Aalami, O. 2019


    BACKGROUND: Supervised exercise therapy (SET) is an inexpensive, low-risk, and effective option when compared with invasive therapies for the treatment of patients with peripheral artery disease (PAD) and intermittent claudication. Randomized, controlled trials have demonstrated the benefits of SET in improving maximum walking distance in intermittent claudication patients, and society guidelines recommend SET as first-line therapy. In 2017, the Centers for Medicare & Medicaid Services (CMS) added coverage of SET. We aimed to evaluate the availability and use of SET programs, determine the awareness of SET CMS coverage in the United States, and gauge the academic interest in SET in the vascular community.METHODS: An eight-question online survey regarding SET coverage, reimbursement, barriers to prescription, and SET use was sent to 900 vascular surgeons, cardiologists, and vascular medicine physicians across the United States. The most recent 2-year programs for the Vascular Annual Meeting, Midwestern Vascular Society, Eastern Vascular Society, and Western Vascular Society were reviewed to identify SET-related abstracts and gauge academic interest and awareness for SET within the vascular surgery community.RESULTS: We received 135 physician responses (15%) to the survey. All 50 states were represented. The majority of responders (54%) stated that there was no SET program at their facility, and 5% did not know if there was a SET program available. Of those who did have a SET program available, 81% were associated with cardiac rehabilitation and 19% had a PAD-specific program. A significant number of physicians (49%) had never referred a patient for SET. Twenty-six percent were not aware that CMS covered SET sessions. Of the physicians who were aware of CMS reimbursement, 36% had never referred a patient to a SET program. Of all surveyed, 98% indicated they would refer patients to a SET program if one was available. Top barriers to use of a SET program included (1) no SET center availability and (2) significant cost or travel expense to the patient. A review of major vascular surgery meeting programs for the last 2years yielded no identification of a SET-related abstract.CONCLUSIONS: There is a lack of both availability and use of SET for patients with PAD with claudication, despite guideline recommendations and CMS reimbursement for SET sessions in the United States. When SET is offered, it is typically through cardiac rehabilitation programs which is not focused on PAD. Travel distance, lack of SET program availability, and low reimbursement rates are primary areas that could be addressed to improve use.

    View details for DOI 10.1016/j.jvs.2019.08.238

    View details for PubMedID 31699514

  • Mobile Engagement for Walking in Patients With Claudication Aalami, O., Savage, D., Rens, N., Meng, E., Triggs, D. MOSBY-ELSEVIER. 2019: E230
  • National Assessment of Availability, Awareness, and Utilization of Supervised Exercise Therapy for Peripheral Artery Disease in Patients With Intermittent Claudication Dua, A., Savage, D., Rens, N., Gandhi, N., Brooke, B. S., Corriere, M., Jackson, E., Aalami, O. MOSBY-ELSEVIER. 2019: E55–E56