Footwear that “feels”

Leprosy is a rare, poverty-related, neglected tropical disease of the skin and nerves. In 2019, the World Health Organization (WHO) reported 202,488 new cases of leprosy globally. India reported 114,451 new cases of leprosy in 2019, more than 50% of the global new leprosy caseload (Source: Weekly Epidemiological Record (WER), 10 September 2021, Vol. 96, No. 36 (pp. 421–444) [EN/FR] - World | ReliefWeb https://reliefweb.int/report/world/weekly-epidemiological-record-wer-10-september-2021-vol-96-no-36-pp-421-444-enfr). When leprosy is detected late, as is the case even today, damage to the nerves leads to lifelong and irreversible loss of sensation, and muscle imbalance. Diabetes detected late and poorly managed does the same thing. The ability to feel pressure and pain is what protects us from injury during our activities of daily living. WHO estimates that around 6-7% of all new leprosy cases have established nerve damage at the time of diagnosis. This adds up to more than 130,000 people in the world living with leprosy nerve damage today, if we consider just the past 15 years, of which more live in India than anywhere else in the world.

Excessive pressure from prolonged walking or standing on feet which have lost their sensation of pain, causes pressure injury and ulcers. The ulcers are a stigmatizing hallmark of leprosy, and can only heal with complete rest and often hospitalization. Restricting people from carrying out their activities of daily living to allow for these ulcers to heal, is inconvenient, expensive, and stressful, affecting productivity and income of people who earn around $6-7 a day doing agricultural or manual labor on a daily wage basis; we estimate this results in a loss of income and productivity of nearly two-thirds of their income annually! Added to this, the ulcers recur on resuming daily activity. Without protective sensation, the person literally walks their way to amputation.

American Leprosy Missions (ALM) is a long time partner of the Schieffelin Institute of Health – Research & Leprosy Center (SIHRLC), in Karigiri, India, one of the world’s leading leprosy research centers. SIHRLC sees 1,300-1,800 cases with leprosy neuropathy every year, and provides more than 2,000 consultations annually for the treatment of plantar ulcers. More than 250 patients are admitted every year for nearly a month-long stay and management of severe ulcers, and undergo major debridement surgery and amputations. Around 2,000 special footwear, assistive devices, and artificial limbs are manufactured and dispensed at the hospital every year for patients with leprosy neuropathic feet. 

In 2019, we came up with an innovative idea for leprosy neuropathic feet. What if footwear could alert the wearer through some sort of signal, like a sound or a vibration, when plantar pressures peaked to dangerously high levels, so they immediately altered their gait or took the weight off the high-risk foot? Could this be a feasible solution to replace the permanently lost sensation and perform the same protective role? 

ALM supported the development and testing of the first prototype tactile sensory feedback system during 2019-2022. The artificial biofeedback system used tactile force resistive sensors embedded in footwear insoles, to identify key plantar pressures at specific points on the sole of the foot, when walking and standing during activities of daily living. The force resistive sensors transferred plantar pressure data to a transmitter via a data acquisition system. Peak pressures identified at specific points on the sole helped set the threshold limits for these specific points. The data acquisition system used Bluetooth technology to provide biofeedback to the wearer, through an audible alarm fitted on a device on the footwear, when pressures crossed the set threshold level of the calibrated insole sensors. 

Patients with neuropathic feet who wore and tested the prototype, were educated in the physiotherapy and occupational therapy department on how to walk to maintain plantar pressures within their permissible threshold levels and reduce the force exerted on their neuropathic foot/feet. Despite this education, and because of the sensory loss, there would be times when peak plantar pressures would build up. This is when the biofeedback mechanism came into play, setting off an audible signal that prompted them to alter their gait and release the pressure from off the foot. The biofeedback helped them subconsciously ‘learn’ how to protect their feet while walking and standing. The results were promising: none of  the 30 persons with leprosy neuropathic feet who wore the prototype for a year developed ulcers, whereas we would anticipate that 70% of patients (or an estimated 21 people in the study) would have developed ulcers based on clinical observations. 

Our solution will impact the lives of thousands of people with leprosy plantar anesthesia preventing them from developing ulcers; keeping them off the slippery slope to amputation and poverty. In 2020, the World Health Organization (WHO) reported 127,558 new cases of leprosy globally. WHO estimates that around 6-7% of new leprosy cases have established nerve damage at the time of diagnosis. This adds up to more than 130,000 people in the world living with leprosy nerve damage today, if we consider just the past 15 years. The highest number of these people live in India which has the world’s highest leprosy burden. Leprosy is an ancient disease associated with deep seated stigma in India. Visible ulcers and disability lead to multidimensional consequences: stigma and discrimination experienced by the person and their family, restrictions in activities of daily living, loss of employment, and worsening poverty. A community stigma survey conducted by ALM in March 2022, revealed that the stigma towards leprosy is very strong, with a significant negative bearing on the quality of life for people with leprosy disability in India specifically; there is overwhelming evidence of high burden of the consequences of stigma associated with leprosy globally.

Leprosy is a disease of poverty; our patients are mostly agricultural or manual laborers working for a daily wage of around $6-7 per day. Once nerve damage and disability set in, the ability to walk and work is severely curtailed. Specialized leprosy care is limited to very few hospitals in India. Leprosy is among a group of 20 diseases that are termed neglected tropical diseases (NTDs) because of their low public health priority, and consequently funding. People with leprosy sensory loss need long-term care which is seldom available in an already overstrained health system. Therefore, people usually first access care closer to home through non-formal medical practitioners and when the ulcers do not improve, try to seek out hospitals that will treat them. Repeated visits to health care facilities for treatment, and time off from work incur out of pocket expenditure and loss of wages. On an average, a person with leprosy neuropathic feet and recurrent plantar ulcers may require five to six hospital admissions annually with an average duration of three-weeks’ hospital stay and a minimum of two follow-up visits to the hospital after discharge. Patients usually travel with a family member (as an attendant) to help them during the travel and hospital stay. Their annual loss of wages and travel costs for them and their attendant could range anywhere from USD $1,000 -1,500 depending on the distance from their homes to a specialized leprosy hospital; this care costs nearly a year's wages. At SIHRLC, where health care for leprosy patients is free of cost, the annual expenditure on the care of one patient with neuropathic feet ranges from USD $4,500- 5,000 (on average requiring five admissions, ulcer surgery / amputation, prostheses and other assistive devices). If we can replace their lost protective sensation with something as simple as an insole that “feels” fitted into any kind of footwear, at a current estimated cost of USD $400 for a pair of shoes that could last for up to two years depending on usage, we are addressing a permanent need in a most cost effective and practical way.

While the economic benefits – either to the potential patient or a cost covered by SIHRLC and ultimately global donors – the impact goes way beyond this for the leprosy patient. It prevents lost time off work and future disabilities, it allows them to continue providing for themselves and their families, it keeps them connected in the community as productive members of society, and more. The social and emotional benefits of being self-sufficient are innumerable. 

American Leprosy Missions and its partner SIHRLC have been involved in leprosy related healthcare since their establishment in 1906 and 1955 respectively. SIHRLC is a pioneer in research and innovation, and professional training for the management of the leprosy neuropathic foot. Staff at SIHRLC are well acquainted with the multifaceted problems of leprosy and seek to address these needs in an integrated and holistic fashion. ALM has worked intimately with SIHRLC on many projects and endeavors, with co-design, technical support, staff support, and financial support. The Institute manages over 2,000 consultations for leprosy neuropathic feet every year, on an outpatient and inpatient basis; hospital and community outreach programs for leprosy care have patient education and counseling as an integral part of leprosy management. The Institute constantly incorporates the learning from research, evaluations, and patient feedback into improving patient care and management.

SIHRLC is a “first in care” center. It pioneered reconstructive and tendon transfer surgery to correct leprosy disability in hands, feet and eyes in the late 1940s. The microcellular rubber (MCR) insoles that are used in footwear for leprosy the world over were first manufactured in SIHRLC in 1962 and today, SIHRLC supplies MCR footwear and MCR sheets to the National Leprosy Programme and other non-governmental organizations  involved in leprosy care in India. The Footcare Center for leprosy was established at SIHRLC in 1982. In 2008, the Institute was recognized as a “Center of Excellence for Foot Care'' by the World Diabetes Foundation. In 2004, American Leprosy Missions received a USAID ASHA grant for SIHRLC’s MCR manufacturing unit and prosthetics and orthotics workshop which helped in meeting the demand for MCR sheets and footwear from the National Leprosy Programme and NGO hospitals. In 2021, American Leprosy Missions supported the development of the Computer Aided Designing (CAD) and Computer Aided Manufacturing (CAM) unit for 3D foot scanning and custom insole fabrication. In 2021, ALM received another USAID ASHA grant for a Prosthetics and Orthotics Center at SIHRLC for innovation, research, and development of newer prostheses and orthoses and improved management of people with lower limb disabilities. Both organizations' research on the management of leprosy neuropathic feet has been published in many peer-reviewed journals and presentations have been made in international conferences; staff have contributed to various textbooks of leprosy. 

While operating at the highest level of technology, the preliminary prototype design utilized inclusive practices and was conceptualized in consultation with people affected by leprosy experiencing disability. The good rapport and trust between SIHRLC and its patients, ensured us 30 test users who faithfully wore and tested the preliminary low-cost, crude prototype for an entire year. The team’s regular interaction with the users through focus group discussions and in-depth interviews elicited their perspectives on the usage of the product. Their inputs for improvement have been taken into consideration in subsequent designs of the device. A simple example of user feedback in improving design, is changing the audible signal to a vibration that would call less attention to the footwear, when worn in public.

There are specific financial, technical, cultural, and legal barriers that we believe the Challenge can help us overcome. 

• Financially, the MIT Solve Horizon Prize would help us in design iterations and modifications; the prize money would be used to develop a unique insole which has the sensors incorporating the data acquisition system and transmission system, and fund acceptable footwear designs into which the insole can be fitted. We are now working on piloting an improved design, based on user feedback and an evaluation of the project. We plan to pilot the improved design with 200 to 400 users, depending on fund availability, learn from it and make iterations for the most acceptable and user friendly insole. Currently, our solution has the potential to serve at least 1,500 new cases of leprosy plantar anesthesia who are seen in SIHRLC annually. Through our linkages with other leprosy hospitals (over 30 facilities) and the National Leprosy Program, our solution can serve an estimated 8,000 annual new cases of leprosy plantar anesthesia in India alone. If we extend this to the diabetic foot, we could serve millions; India reported 74 million new cases of diabetes in 2020, an estimated 50% of whom will eventually develop neuropathy. Additionally, the Prize will fund monitoring of user outcomes and impact.
• Technically, we hope to collaborate with MIT for their technical expertise in developing and refining our product. 
• Culturally, we face footwear barriers in India: traditionally, people do not wear footwear inside the home and if they do, these are usually flip flops that can be easily removed and washed; rural people in hotter climates prefer open sandals and footwear would need to be waterproof for use in agricultural work; and footwear designs for women need to adhere to the current Indian market designs. Therefore, not all insoles can be fitted into closed shoes, some have to be incorporated into open footwear designs. The same holds true when we consider incorporating the insoles in footwear that would be culturally accepted across the globe both in developing and developed countries. 
• Legally, we would need support in procuring Intellectual Property rights and patents etc. if the product is to be marketed in countries other than India, either as a separate product (insole) or designed with the footwear.

To our knowledge, a continuous biofeedback of plantar pressures with a follow-up alert mechanism in real-time for individuals with neuropathic feet is currently not available anywhere in the world, but most certainly not in India. Footwear for neuropathic feet available in the market today offer softer, cushioned insoles which claim to relieve plantar pressure. Our artificial biofeedback system using tactile resistive sensors in footwear insoles, identifies key plantar pressures at specific points on the sole, when walking and standing during activities of daily living. Peak pressures identified set the threshold limits for that foot and the data acquisition system uses Bluetooth technology to provide biofeedback in real-time when pressures cross the set threshold levels, prompting the wearer to take corrective measures to prevent pressure build up and tissue breakdown. We offer a unique and scientific solution that can be used by any individual irrespective of their gender and sociocultural differences. The Insoles can easily be customized and fabricated to fit standard footwear styles within a few hours.

Our solution is simple, practical, and cost effective; used on a daily basis, it can prevent a first ulcer from ever occurring, retaining the person’s ability to walk and work. It can keep people out of hospital and save health expenditure incurred in the long term management of people with chronic foot ulcers. Our analysis using SIHRLC’s data  shows that a $400 pair of footwear with our insoles can save up to $7,000 in combined out-of-pocket and health system expenditure per patient annually. Additionally, our solution has the potential to avert the mental distress and stigma experienced by people living with chronic plantar ulcers. 

In terms of being catalytic, our solution has immense potential to impact people with sensory loss in their feet due to leprosy, diabetes, and other neurological disease conditions in India and across the world. As we have earlier stated, our linkages with leprosy hospitals in India and the National Leprosy Programme, can extend our solution to an estimated 8000 annual new cases of leprosy plantar anesthesia in India alone. If we include diabetic feet, India reported 74 million new cases of diabetes in 2020, an estimated 50% of whom will eventually develop neuropathy. Projecting this globally, our solution has the potential to impact millions through an insole that “feels” and that can be inserted in most footwear. We expect that the market will create new, acceptable footwear designs that can accommodate such an insole.

In ONE year, we will complete the design and development of a reliable insole with sensors incorporating the data acquisition system and transmission system, and that can be fitted into most footwear models. We would use advanced technologies to design and develop an affordable cost effective system that could be used by clients irrespective of their gender and socio-economic status.

In FIVE YEARS, our insoles will penetrate the global market for recommended use by all people with neuropathic feet - as  insoles for any kind of open and closed footwear, providing an equitable, affordable, and accessible solution to prevent the detrimental complications of neuropathic feet.

Our objectives are:

1. > 80 % reliability of the insoles in identifying peak plantar pressure areas of the feet while walking and other functional activities, above which plantar ulcers will occur.

2. > 80% reported compliance in wearing the footwear with insoles, and gait modification to prevent peak pressure, indicating usability and acceptance of the footwear.

3. < 30% of users develop a first ulcer, indicating efficacy.

Excessive pressure from prolonged walking or standing on neuropathic feet with permanent sensory loss causes recurring pressure injury and ulcers, leading to avoidable loss of mobility and productivity, and incurring excessive health expenditure. Cost effective solutions, like our tested tactile biofeedback system, that can predict and prevent excessive plantar pressures early, would prevent recurrent pressure ulcers, allowing the person to continue their normal life. 

Excessive force on the anesthetic foot leads to tissue breakdown and ulcers. The sensory feedback system through the force-sensing resistors (FSRs) provides feedback on  plantar pressure variations. Integrated circuits and electronic devices are used for transferring the data from the sensors to the microcontroller which triggers the alerting device. The threshold pressure value for triggering the alert is controlled by the open-source Arduino IDE (Integrated Development Environment) software. A Micro Cellular Rubber (MCR) insole is trimmed for accurate fit and plantar pressure prone areas identified by a Harrison Mat are marked for the placement of the FSRs. The FSRs are then connected to Arduino UNO which acts as a data acquisition board. Arduino UNO used in the data acquisition system is an open source microcontroller with a feature of compatible programmability. The Bluetooth module (HC-05) integrates and shares the data to the computer as well as to actuate the coin vibration motor. The Bluetooth module works with the input of 3.3-6V and 30mA current.

The FSR heads are placed in the identified plantar pressure regions to obtain accurate pressure values. Respective force values exerted on the FSR heads placed at the plantar pressure area of the foot are obtained through the serial monitor. A 10Volt battery is used to power this circuit. All Force sensitive resistors and the circuit board are adequately soldered to minimize the error caused by misplacement of circuits. After integration of the circuit, the FSR heads are placed at the plantar pressure prone areas of the foot identified on the insole. The insole with the sensors is fixed into the patient’s footwear to obtain the values of forces acting on the plantar region of the foot while walking. The data acquired are evaluated to recognize the peak pressure on the plantar area of the foot which helps in determining the threshold limit for integrating an alerting circuit.

The coin vibrator is connected to the pin of the Arduino which acts as the alerting terminal. The vibration depends on the force applied on the force sensitive resistor head of the FSRs. This specialized insole triggers the vibrator when the force on the sensors exceeds the threshold limit. The threshold limit for a patient is identified based on their repeated walking pattern while wearing the insoles, and the sensors are calibrated for these threshold values. The sensory feedback system in the footwear with the insole is provided to the patient and the pressure variations on doing their activities of daily living are recorded and monitored through the data acquisition system. The data acquisition system using Bluetooth technology, provides biofeedback to the wearer, through a vibration, when pressures cross the set threshold levels of the calibrated insole sensors, causing the wearer to take corrective measures to offload the pressure. It also subconsciously ‘teaches’ the wearer how to walk and stand to prevent peak plantar pressures from building up.

At the forefront of ALM and SIHRLC, Karigiri’s approach to serving marginalized people affected by leprosy, and other neglected tropical diseases, is inclusion. Over 20% of ALM’s  board are persons affected by leprosy. They are deeply committed to our mission, attend events, join staff weekly for meetings, and travel to project locations as possible. “Beneficiaries” are included in the design of tools and technology, as demonstrated by this project as well as other adaptive technology we are working on. ALM includes and is in regular contact with leprosy affected advocacy groups, like MORHAN in Brazil. 

ALM’s staff is diverse and is dispersed across the US and staff are located in Ghana, Libera, India and the UK hailing with experience every continent except Antarctica. Many have immigrant stories to share and celebrate dual citizenship. Our CEO was raised in the Democratic Republic of Congo and most staff have lived and worked cross-culturally. While we are required by the IRS to have a “headquarters” we are truly dispersed organization that accommodates “work from home” and strives to include everyone regardless of their location and work situation. 

Our programs empower women in traditional societies and help them to advocate for government healthcare coverage for which they have a right to access. 

SIHRLC is committed to inclusivity. We are committed to serve people affected by leprosy and people with physical disabilities, working to improve their participation in community and family life. We have two people with disabilities (one affected by leprosy with deformities corrected by surgery and another a bilateral above-knee-amputee) employed as staff. As far as
gender is concerned, we have 113 male staff and 106 female staff. In our education courses we have 156 males and 178 females enrolled.

Most of ALM’s programs are implemented through local partners like SIHRLC, Karigari which have deep local knowledge to provide excellent care – and truly innovative solutions – in their communities and context. ALM is proud to work with partners that are locally-led and developed. 

SIHRLC, Karigiri -MIT Solve Horizon Prize

Footwear that “feels”

Social Business Model Canvas 

Key Resources

• Expertise in management of neuropathic feet (available).

• Experienced team with the skills required to design and develop the solution (available).

• A large patient base to test the solution and monitor its impact (both leprosy and diabetic patients are available).

• Infrastructure to manufacture insoles and footwear in-house. (available).

• Technical expertise for an insole incorporating the entire biofeedback system (seek collaboration)

• Technical expertise for marketable footwear designs to incorporate the insole (seek collaboration)

• Investment to take the pilot to growth stage (seek collaboration)

• Legal: intellectual property rights, patents, licensing, distribution agreements (seek collaboration)

Key Activities

• Selection of patients with neuropathic feet who will benefit from the insoles

• Consent and enrolling the patients in our study

• Fabrication of the customized insole and footwear with the sensory feedback system

• Fitting, trial, and patient education

• Regular feedback from the users

• Focus group discussions and individual interviews with users at planned times in their villages

• Clinical follow up of the users at Karigiri every 6 months for direct observations of feet and footwear, and personal interactions.

• Regular analysis of data

• Modifications to footwear as indicated by user feedback and data analysis

• Research publications

• Presentations at conferences

• Networking with organizations that can become potential customers

• Fundraising

• Intellectual property rights, patents, licensing, and distribution agreements

Type of Intervention

• Product: Design and fabrication of a tactile sensory biofeedback in footwear for neuropathic feet

• Service: The product will be supported by patient education on their disease condition and measures to protect their feet while using the product, with clinical care available for any leprosy/diabetic related, and foot related complications.

Segments

Beneficiaries 

• Individuals with neuropathic feet from leprosy, diabetes, and similar neurological conditions

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Customers 

• Non-government and government healthcare organizations working in the fields of leprosy and diabetes 

• Paying clients with neuropathic feet who are looking for ways to protect their feet

Value Proposition

User value proposition

• A pair of these insoles fitted into everyday footwear will allow the person to continue their activities of daily living.

• The insoles will “feel” for their neuropathic feet, alerting them in real-time to offload dangerous pressure build up.

• This will prevent pressure ulcers and keep the person out of hospital.

• Time and expenses saved. Mobility and productivity retained.

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Impact Measures

• An ulcer-free life for individuals with neuropathic feet, allowing them to continue the ability to walk and work.

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Customer Value Proposition

• Decreases burden on government and government healthcare organizations involved leprosy and diabetes care 

• People with neuropathic feet continue to be mobile, active, and productive despite permanent loss of sensation in their feet. 

• In a future scenario, when our customers may be commercial partners, there will be profit in this solution for them.

Partners & Key Stakeholders 

• Non-government and government healthcare organizations involved leprosy/diabetes care.

• National Leprosy Programme

• International Federation of Leprosy Associations (ILEP)

• Individuals with neuropathic feet looking for ways to protect their feet.

• We envision footwear manufacturers as commercial partners in the growth stage.

Channels

• Currently, in this pilot phase, our users are selected from among the leprosy patients consulting at SIHRLC.

• We are not selling the product in this pilot phase. 

Cost Structure

Our biggest expenditure areas:

•  Developing the data acquisition and transmitting systems

• Procurement of sensors

• Developing the optimal insole

• Appropriate footwear designs

• Development of prototypes for production

• Acquiring materials and components for production

• Establishing IP rights and patents

Once technical and aesthetic design is complete and production can be scaled, we envision that per unit costs will decrease, allowing the product to become commercially viable and attractive to investors and/or manufacturers.

Surplus

Any profits would be invested in:

• Improving the device and in promoting the product.

• Subsidized care for people from low socioeconomic status.

• Expanding market reach to more customers and beneficiaries.

• Developing more products and applications of the technology.

Revenue

• The current model relies on donated funds from the NGO sector but we believe the product has potential to become self-sustaining.

The idea of developing the product due to the plight of the leprosy affected with insensitive feet, suffering with recurrent ulcers, stigma, discrimination, and poverty. For sustainability, we plan to work on a social enterprise model, where we will continue serving leprosy affected patients free of cost, as this is the core mission of both partners, while generating revenue by selling our product to customers and providing clinical services to paying clients who can afford it, to subsidize our leprosy related services. Our linkages and partnerships within the leprosy and health sector in India and other leprosy endemic countries will help us expand the enterprise’s customer base. The business would facilitate creating a funding mechanism that would expand the mission of the organizations. We will continue to seek funding to support the core leprosy foot care services and continued research and development of this product and other products useful in the management of the leprosy anesthetic foot. If we are successful in obtaining a patent for our solution, we can expect sustained funding if the solution is accepted by the Indian and global market.

The concept for Footwear that ‘feels’ is the culmination of a long collaboration between ALM and SIHRLC in researching and developing innovative ways to relieve and treat patients afflicted with leprosy, which has included these investments in the technology to date: 

ALM has invested $67,000 in the development and testing of this solution over three years.  

• In 2004, ALM received a USAID ASHA grant of $222,947 for SIHRLC’s MCR manufacturing unit, and prosthetics and orthotics workshop; this helped in meeting the demand for MCR sheets and footwear from the National Leprosy Programme and NGO hospitals. 
• In 2021, ALM invested $110,00 in a Computer Aided Designing (CAD) and Computer Aided Manufacturing (CAM) unit for 3D foot scanning and custom insole fabrication at SIHRLC. 
• In 2021, ALM received a USAID ASHA grant of $936,624, for a Prosthetics and Orthotics Center at SIHRLC for innovation, research, and development of newer prostheses and orthoses and improved management of people with lower limb disabilities.  

SIHRLC is committed to providing its services free of charge to leprosy patients, but it does generate revenue from paying clients for its non-leprosy clinical specialties. Around 44% of SIHRLC’s annual budget of $2.5 million is met by revenue from paying patients, (around $1.1 million annually). The rest of the expenditure budget is raised through training programs and allocated grants and donations. Approximately 10% of the patient generated revenue is allocated to subsidizing treatment of leprosy patients. 59% of the footwear unit's cost is met through paying clients. The rest 41%  is subsidized by donations and non leprosy patient generated revenue. Some revenue is also generated through the sale of footwear and MCR sheets to the National Leprosy Programme, other leprosy organizations and paying clients. This solution has the potential to produce revenue at scale and become financially sustainable due to its broad application to leprosy and diabetes patients.