Identifying individuals most at risk for diabetic retinopathy progression and intervening early can limit vision loss and reduce the costs associated with managing more advanced disease. The purpose of this study was to identify factors associated with progression from nonproliferative diabetic retinopathy (NPDR) to proliferative diabetic retinopathy (PDR).
RESEARCH DESIGN AND METHODS
This was a retrospective cohort analysis using a claims database of all eye care recipients age ≥30 years enrolled in a large managed-care network from 2001 to 2009. Individuals with newly diagnosed NPDR were followed longitudinally. Multivariable Cox regression analyses identified factors associated with progression to PDR. Three- and five-year probabilities of retinopathy progression were determined.
Among the 4,617 enrollees with incident NPDR, 307 (6.6%) developed PDR. After adjustment for confounders, every 1-point increase in HbA1c was associated with a 14% (adjusted hazard ratio 1.14 [95% CI 1.07–1.21]) increased hazard of developing PDR. Those with nonhealing ulcers had a 54% (1.54 [1.15–2.07]) increased hazard of progressing to PDR, and enrollees with nephropathy had a marginally significant increased hazard of progressing to PDR (1.29 [0.99–1.67]) relative to those without these conditions. The 5-year probability of progression for low-risk individuals with NPDR was 5% (range 2–8) and for high-risk patients was 38% (14–55).
Along with glycemic control, nonophthalmologic manifestations of diabetes mellitus (e.g., nephropathy and nonhealing ulcers) are associated with an increased risk of diabetic retinopathy progression. Our retinopathy progression risk score can help clinicians stratify patients who are most at risk for disease progression.
Introduction. Charcot foot is a rare and devastating complication of diabetes. While some risk factors are known, debate continues regarding etiology. Elucidating other associated disorders and their temporal occurrence could lead to a better understanding of its pathogenesis. We applied a large data mining approach to Charcot foot for elucidating novel associations. Methods. We conducted an association analysis using ICD-9 diagnosis codes for every patient in our health system (n = 1.6 million with 41.2 million time-stamped ICD-9 codes). For the current analysis, we focused on the 388 patients with Charcot foot (ICD-9 713.5). Results. We found 710 associations, 676 (95.2%) of which had a P value for the association less than 1.0 × 10−5 and 603 (84.9%) of which had an odds ratio > 5.0. There were 111 (15.6%) associations with a significant temporal relationship (P < 1.0 × 10−3). The three novel associations with the strongest temporal component were cardiac dysrhythmia, pulmonary eosinophilia, and volume depletion disorder. Conclusion. We identified novel associations with Charcot foot in the context of pathogenesis models that include neurotrophic, neurovascular, and microtraumatic factors mediated through inflammatory cytokines. Future work should focus on confirmatory analyses. These novel areas of investigation could lead to prevention or earlier diagnosis.
Many of the physiological changes that lead to diabetic foot ulceration, such as muscle atrophy and skin hardening, are manifested at the foot–ground interface via pressure and shear points. Novel shear-reducing insoles have been developed, but their magnitude of shear stiffness has not yet been compared with regular insoles. The aim of this study was to develop an apparatus that would apply shear force and displacement to an insole’s forefoot region, reliably measure deformation, and calculate insole shear stiffness.
An apparatus consisting of suspended weights was designed to test the forefoot region of insoles. Three separate regions representing the hallux; the first and second metatarsals; and the third, fourth, and fifth metatarsals were sheared at 20 mm/min for displacements from 0.1 to 1.0 mm in both the anteroposterior and mediolateral directions for two types of insoles (regular and shear reducing).
Shear reduction was found to be significant for the intervention insoles under all testing conditions. The ratio of a regular insole’s effective stiffness and the experimental insole’s effective stiffness across forefoot position versus shear direction, gait instance versus shear direction, and forefoot position versus gait instance was 270% ± 79%, 270% ± 96%, and 270% ± 86%, respectively. The apparatus was reliable with an average measured coefficient of variation of 0.034 and 0.069 for the regular and shear-reducing insole, respectively.
An apparatus consisting of suspended weights resting atop three locations of interest sheared across an insole was demonstrated to be capable of measuring the insole shear stiffness accurately, thus quantifying shear-reducing effects of a new type of insole.
diabetic foot; diabetic foot ulceration; orthotic devices; shear; shear stiffness
People who have extremely high arched feet or pes cavus often suffer from substantial foot pain. Custom-made foot orthoses (CFO) have been shown to be an effective treatment option, but their specificity is unclear. It is generally thought that one of the primary functions of CFO is redistributing abnormal plantar pressures. This study sought to identify variables associated with pain relief after CFO intervention.
Plantar pressure data from a randomized controlled trial of 154 participants with painful pes cavus were retrospectively re-analyzed at baseline and three month post CFO intervention. The participants were randomized to a treatment group given CFO or a control group given sham orthoses.
No relationship between change in pressure magnitude and change in symptoms was found in either group. However, redistribution of plantar pressure, measured with the Dynamic Plantar Loading Index, had a significant effect on pain relief (p = 0.001). Our final model predicted 73% of the variance in pain relief from CFO and consisted of initial pain level, BMI, foot alignment, and changes in both Dynamic Plantar Loading Index and pressure–time integral.
Our data suggest that a primary function of effective orthotic therapy with CFO is redistribution of abnormal plantar pressures. Results of this study add to the growing body of literature providing mechanistic support for CFO providing pain relief in painful foot conditions. The proposed model may assist in better designing and assessing orthotic therapy for pain relief in patients suffering painful cavus foot deformity.
Randomized controlled trial: ISRCTN84913516
Foot pain; Pes cavus; Plantar pressure; Modeling pain relief; Probability distribution of peak pressure; Dynamic plantar loading index
Most cases of lower extremity limb loss in the United States occur among people with diabetes who have a diabetic foot ulcer (DFU). These DFUs and the associated limb loss that may occur lead to excess healthcare costs and have a large negative impact on mobility, psychosocial well-being, and quality of life. The strategies for DFU prevention and management are evolving, but the implementation of these prevention and management strategies remains challenging. Barriers to implementation include poor access to primary medical care; patient beliefs and lack of adherence to medical advice; delays in DFU recognition; limited healthcare resources and practice heterogeneity of specialists. Herein, we review the contemporary outcomes of DFU prevention and management to provide a framework for prioritizing quality improvement efforts within a resource-limited healthcare environment.
foot ulcer; diabetes; peripheral vascular disease; diabetic neuropathy; delivery of healthcare; physician's practice patterns
The purpose of this study was to evaluate a new method showing how custom foot orthoses (CFO) improve dynamics of plantar loading. The method is based on the probability distribution of peak pressure time series and is quantified using the Regression Factor (RF). RF is a least square regression slope between the experimentally observed plantar pressure magnitude probability distribution and a modeled Gaussian shape. Plantar pressure data from a randomized controlled trial of 154 participants with painful Pes Cavus were retrospectively re-analyzed. The participants were randomized to an active treatment group given CFO or a control group given sham orthoses. The location of 2nd Peak pressure as a percentage of stance time (PLoc2) and its magnitude (PM2) was also calculated. In addition, plantar pressure data were collected on 23 healthy volunteers with normal foot alignment and no foot pain. Results demonstrated Pes Cavus had a significantly lower RF than healthy participants (0.30 v. 0.51; p<10−7). PM2 was reduced in both active and control groups. However, RF and the PLoc2 were only changed in the active group (p<0.005) without any significant change in the control group (p>0.5). This study suggests that painful Pes Cavus alters the shape of probability distribution of plantar loading during walking and CFO are an effective therapeutic solution that can significantly improve it. Further use of the RF index and 2nd peak pressure location as an outcome measure for treatment of foot and ankle deformities is suggested.
Pes Cavus; custom foot orthoses; randomized controlled trial; gait; orthotic devices; outcome assessment (health care)
Diabetic foot ulcers are a major source of morbidity, limb loss, and mortality. A prolonged inflammatory response, extracellular matrix degradation irregularities, and increased bacteria presence have all been hypothesized as major contributing factors in the delayed healing of diabetic wounds. Collagen components such as fibroblast and keratinocytes are fundamental to the process of wound healing and skin formation. Wound dressings that contain collagen products create a biological scaffold matrix that supports the regulation of extracellular components and promotes wound healing.
A systematic review of studies reporting collagen wound dressings used in the treatment of Diabetic foot ulcers was conducted. Comprehensive searches were run in Ovid MEDLINE, PubMed, EMBASE, and ISI Web of Science to capture citations pertaining to the use of collagen wound dressings in the treatment of diabetic foot ulcers. The searches were limited to human studies reported in English.
Using our search strategy, 26 papers were discussed, and included 13 randomized designs, twelve prospective cohorts, and one retrospective cohort, representing 2386 patients with diabetic foot ulcers. Our design was not a formal meta-analysis. In those studies where complete epithelialization, 58% of collagen-treated wounds completely healed (weighted mean 67%). Only 23% of studies reported control group healing with 29% healing (weighted mean 11%) described for controls.
Collagen-based wound dressings can be an effective tool in the healing of diabetic foot wounds. The current studies show an overall increase in healing rates despite limitations in study designs. This study suggests that future works focus on biofilms and extracellular regulation, and include high risk patients.
bio films; matrix; wound healing; scaffold; dressings
Purpose: A challenge in ocular preventive medicine is identification of patients with early pathological retinal damage that might benefit from nutritional intervention. The purpose of this study is to evaluate retinal thinning (RT) in early atrophic age-related macular degeneration (AMD) against visual function data from the Zeaxanthin and Visual Function (ZVF) randomized double masked placebo controlled clinical trial (FDA IND #78973). Methods: Retrospective, observational case series of medical center veterans with minimal visible AMD retinopathy (AREDS Report #18 simplified grading 1.4/4.0 bilateral retinopathy). Foveal and extra-foveal four quadrant SDOCT RT measurements were evaluated in n = 54 clinical and ZVF AMD patients. RT by age was determined and compared to the OptoVue SD OCT normative database. RT by quadrant in a subset of n = 29 ZVF patients was correlated with contrast sensitivity and parafoveal blue cone increment thresholds. Results: Foveal RT in AMD patients and non-AMD patients was preserved with age. Extrafoveal regions, however, showed significant slope differences between AMD patients and non-AMD patients, with the superior and nasal quadrants most vulnerable to retinal thinning (sup quad: −5.5 μm/decade thinning vs. Non-AMD: −1.1 μm/decade, P < 0.02; nasal quad: −5.0 μm/decade thinning vs. Non-AMD: −1.0 μm/decade, P < 0.04). Two measures of extrafoveal visual deterioration were correlated: A significant inverse correlation between % RT and contrast sensitivity (r = −0.33, P = 0.01, 2 Tailed Paired T) and an elevated extrafoveal increment blue cone threshold (r = +0.34, P = 0.01, 2 Tailed T). Additional SD OCT RT data for the non-AMD oldest age group (ages 82–91) is needed to fully substantiate the model. Conclusion: A simple new SD OCT clinical metric called “% extra-foveal RT” correlates well with functional visual loss in early AMD patients having minimal visible retinopathy. This metric can be used to follow the effect of repleting ocular nutrients, such as zinc, antioxidants, carotenoids, n-3 essential fats , resveratrol and vitamin D.
atrophic age-related macular degeneration (AMD); spectral domain OCT (SD OCT); contrast sensitivity function (CSF); extrafoveal blue-cone increment thresholds
Golfers have better balance than their age-matched counterparts; however, it is uncertain if this persists during the swing as a function of skill level. The purpose of the study was to investigate dynamic postural control (center of mass (COM) motion) measured during different phases of the swing in golfers of varying proficiency. Eighteen healthy golfers were grouped by handicap: novice (no handicap, n = 7), intermediate (handicap 15-19, n = 7), and advanced (handicap 9-14, n = 4). Indoor testing was performed hitting 3 tee shots using a common driver. A five-camera (60 Hz) motion analysis system (9 markers) was used to extract kinematics data. There were no significant group differences in gender, age, or BMI. Advanced players had lower COM displacement with respect to address at the time of maximum arm speed (p = 0. 001) compared to intermediate (57%, p = 0.014) and novice (73%, p = 0.023). These changes persisted after COM distance and time normalization. Advanced golfers had improved COM linearity during the downswing (p < 0.001) compared to intermediate (30%, p = 0.029) and novice (51%, p < 0.001). Advanced players had decreased COM displacement at the time of maximum arm speed and a more linear COM path during the early downswing. Further study should focus on these changes during ball launch conditions.
Key pointsStudies suggest that static and dynamic balance is important in golf. However, none have investigated dynamic postural control during the golf swing in golfers of varying proficiency.Our findings suggest advanced players demonstrated improved postural control at the point of maximum arm speed when compared to less skilled players. Furthermore, center of mass acceleration in advanced players is closer to impact than less-skilled players.We observed an increased center of mass linearity of trajectory during the early downswing for advanced players over novice players. We theorized this strategy may help advanced golfers to improve the economy of COM motion during golf swing and improve the performance of the shot.
Golf Balance; Body worn sensor; postural compensatory strategy.
Objective. Asymmetric plantar temperature differences secondary to inflammation is a hallmark for the diagnosis and treatment response of Charcot foot syndrome. However, little attention has been given to temperature response to activity. We examined dynamic changes in plantar temperature (PT) as a function of graduated walking activity to quantify thermal responses during the first 200 steps.
Methods. Fifteen individuals with Acute Charcot neuroarthropathy (CN) and 17 non-CN participants with type 2 diabetes and peripheral neuropathy were recruited. All participants walked for two predefined paths of 50 and 150 steps. A thermal image was acquired at baseline after acclimatization and immediately after each walking trial. The PT response as a function of number of steps was examined using a validated wearable sensor technology. The hot spot temperature was identified by the 95th percentile of measured temperature at each anatomical region (hind/mid/forefoot). Results. During initial activity, the PT was reduced in all participants, but the temperature drop for the nonaffected foot was 1.9 times greater than the affected side in CN group (P = 0.04). Interestingly, the PT in CN was sharply increased after 50 steps for both feet, while no difference was observed in non-CN between 50 and 200 steps. Conclusions. The variability in thermal response to the graduated walking activity between Charcot and non-Charcot feet warrants future investigation to provide further insight into the correlation between thermal response and ulcer/Charcot development. This stress test may be helpful to differentiate CN and its response to treatment earlier in its course.
Despite the high cumulative plantar stress associated with standing, previous physical activity reports of diabetic patients at risk of foot ulceration have not taken this activity into account. This study aimed to monitor spontaneous daily physical activity in diabetic peripheral neuropathy (DPN) patients and examine both walking and standing activities as important foot-loading conditions.
RESEARCH DESIGN AND METHODS
Thirteen DPN patients were asked to wear a body-worn sensor for 48 h. Body postures (sitting, standing, and lying) and locomotion (walking, number of steps, and postural transition) were extracted.
Patients daily spent twice as much time standing (13 ± 5%) as walking (6 ± 3%). They spent 37 ± 6% of time sitting and 44 ± 8% lying down. The average number of steps per day was 7,754 ± 4,087, and the number of walking episodes was 357 ± 167 with maximum duration of 3.9 ± 3.8 min.
The large portion of DPN patients' time spent standing with the feet loaded requires further consideration when treating and preventing foot ulcers.
Currently, diagnosis of patients with postural instability relies on a rudimentary clinical examination. This article suggests an innovative, portable, and cost-effective prototype to evaluate balance control objectively.
The proposed system uses low-cost, microelectromechanical sensor, body-worn sensors (BalanSens™) to measure the motion of ankle and hip joints in three dimensions. We also integrated resulting data into a two-link biomechanical model of the human body for estimating the two-dimensional sway of the center of mass (COM) in anterior–posterior (AP) and medial–lateral (ML) directions. A new reciprocal compensatory index (RCI) was defined to quantify postural compensatory strategy (PCS) performance. To validate the accuracy of our algorithms in assessing balance, we investigated the two-dimensional sway of COM and RCI in 21 healthy subjects and 17 patients with diabetic peripheral neuropathic (DPN) complications using the system just explained. Two different conditions were examined: eyes open (EO) and eyes closed (EC) for duration of at least 30 seconds. Results were compared with center of pressure sway (COP) as measured by a pressure platform (Emed-x system, Novel Inc., Germany). To further investigate the contribution of the somatosensory (SOM) feedback to balance control, healthy subjects performed EO and EC trials while standing on both a rigid and a foam surface.
A relatively high correlation was observed between COM measured using BalanSens and COP measured using the pressure platform (r = 0.92). Results demonstrated that DPN patients exhibit significantly greater COM sway than healthy subjects for both EO and EC conditions (p < 0.005). The difference becomes highly pronounced while eyes are closed (197 ± 44 cm2 vs 68 ± 56 cm2). Furthermore, results showed that PCS assessed using RCI is significantly better in healthy subjects compared to DPN subjects for both EO and EC conditions, as well as in both ML and AP directions (p < 0.05). Alteration in SOM feedback in healthy subjects resulted in diminished RCI values that were similar to those seen in DPN subjects (p > 0.05).
This study suggested an innovative system that enables the investigation of COM as well as postural control compensatory strategy in humans. Results suggest that neuropathy significantly impacts PCS.
balance; body-worn sensor; diabetic peripheral neuropathy; postural compensatory strategy; sensory feedback
Diabetic foot complications represent significant morbidity and precede most of the lower extremity amputations performed. Peripheral neuropathy is a frequent complication of diabetes shown to affect gait. Glycosylation of soft tissues can also affect gait. The purpose of this review article is to highlight the changes in gait for persons with diabetes and highlight the effects of glycosylation on soft tissues at the foot–ground interface.
PubMed, the Cochrane Library, and EBSCOhost® on-line databases were searched for articles pertaining to diabetes and gait. Bibliographies from relevant manuscripts were also searched.
Patients with diabetes frequently exhibit a conservative gait strategy where there is slower walking speed, wider base of gait, and prolonged double support time. Glycosylation affects are observed in the lower extremities. Initially, skin thickness decreases and skin hardness increases; tendons thicken; muscles atrophy and exhibit activation delays; bones become less dense; joints have limited mobility; and fat pads are less thick, demonstrate fibrotic atrophy, migrate distally, and may be stiffer.
In conclusion, there do appear to be gait changes in patients with diabetes. These changes, coupled with local soft tissue changes from advanced glycosylated end products, also alter a patient’s gait, putting them at risk of foot ulceration. Better elucidation of these changes throughout the entire spectrum of diabetes disease can help design better treatments and potentially reduce the unnecessarily high prevalence of foot ulcers and amputation.
biomechanics; diabetes; foot
Open access to clinics is a management strategy to improve healthcare delivery. Providers are sometimes hesitant to adopt open access because of fear of increased visits for potentially trivial complaints. We hypothesized open access clinics would result in decreased wait times, increased number of podiatry visits, fewer “no shows”, higher rates of acute care visits, and lower minor amputation rates over control clinics without open access.
This study was a national retrospective case-control study of VHA (Veterans Hospital Administration) podiatry clinics in 2008. Eight case facilities reported to have open podiatry clinic access for at least one year were identified from an email survey. Sixteen control facilities with similar structural features (e.g., full time podiatrists, health tech, residency program, reconstructive foot surgery, vascular, and orthopedic surgery) were identified in the same geographic region as the case facilities.
Twenty-two percent of facilities responded to the survey. Fifty-four percent reported open access and 46% did not. There were no differences in facility or podiatry panel size, podiatry visits, or visit frequency between the cases and controls. Podiatry visits trended higher for control facilities but didn’t reach statistical significance. Case facilities had more new consults seen within 30 days (96%, 89%; P = 0.050) and lower minor amputation rates (0.62/1,000, 1.0/1,000; P = 0.041).
The VHA is the world’s largest managed care organization and it relies on clinical efficiencies as one mechanism to improve the quality of care. Open access clinics had more timely access for new patients and lower rates of minor amputations.
Health care; Quality; Access; Evaluation; Delivery of health care; Amputation; Amputation prevention
Many studies have attempted to better elucidate the effect of foot orthoses on gait dynamics. To our knowledge, most previous studies exclude the first few steps of gait and begin analysis at steady-state walking. These unanalyzed steps of gait may contain important information about the dynamic and complex processes required to achieve equilibrium for a given gait velocity. The purpose of this study was to quantify gait initiation and determine how many steps were required to reach steady state walking under three footwear conditions: barefoot, habitual shoes, and habitual shoes with a prefabricated foot orthoses. Fifteen healthy subjects walked 50 meters at habitual speed in each condition. Wearing habitual shoes with the prefabricated orthoses enabled subjects to reach steady state walking in fewer steps (3.5 steps ± 2.0) compared to the barefoot condition (5.2 steps ± 3.0; p=0.02) as well as compared to the habitual shoes condition (4.7 steps ± 1.6; p=0.05). Interestingly, the subjects’ dynamic medial-lateral balance was significantly improved (22%, p<0.05) by using foot orthoses compared to other footwear conditions. These findings suggest that foot orthoses may help individuals reach steady state more quickly and with a better dynamic balance in the medial-lateral direction, independent of foot type. The findings of this pilot study may open new avenues for objectively assessing the impact of prescription footwear on dynamic balance and spatio-temporal parameters of gait. Further work to better assess the impact of foot orthoses on gait initiation in patients suffering from gait and instability pathologies may be warranted.
gait; orthotic devices; outcome assessment (health care)
Patients with diabetes and peripheral neuropathy are at higher risk for falls. People with diabetes sometimes adopt a more conservative gait pattern with decreased walking speed, widened base, and increased double support time. The purpose of this study was to use a multivariate approach to describe this conservative gait pattern.
Male veterans (mean age = 67 years; SD = 9.8; range 37–86) with diabetes (n = 152) participated in this study from July 2000 to May 2001 at the Veterans Affairs Medical Center, White River Junction, VT. Various demographic, clinical, static mobility, and plantar pressure measures were collected. Conservative gait pattern was defined by visual gait analysis as failure to demonstrate a heel-to-toe gait during the propulsive phase of gait.
Patients with the conservative gait pattern had lower walking speed and decreased stride length compared to normal gait. (0.68 m/s v. 0.91 m/s, p < 0.001; 1.04 m v. 1.24 m, p < 0.001) Age, monofilament insensitivity, and Romberg's sign were significantly higher; and ankle dorsiflexion was significantly lower in the conservative gait pattern group. In the multivariate analysis, walking speed, age, ankle dorsiflexion, and callus were retained in the final model describing 36% of the variance. With the inclusion of ankle dorsiflexion in the model, monofilament insensitivity was no longer an independent predictor.
Our multivariate investigation of conservative gait in diabetes patients suggests that walking speed, advanced age, limited ankle dorsiflexion, and callus describe this condition more so than clinical measures of neuropathy.
Lower extremity complications in persons with diabetes have become an increasingly significant public health concern in both the developed and developing world. These complications, beginning with neuropathy and subsequent diabetic foot wounds frequently lead to infection and lower extremity amputation even in the absence of critical limb ischemia. In order to diminish the detrimental consequences associated with diabetic foot ulcers, a com-mon-sense-based treatment approach must be implemented. Many of the etiological factors contributing to the formation of diabetic foot ulceration may be identified using simple, inexpensive equipment in a clinical setting. Prevention of diabetic foot ulcers can be accomplished in a primary care setting with a brief history and screening for loss of protective sensation via the Semmes-Weinstein monofilament. Specialist clinics may quantify neuropathy, plantar foot pressure, and assess vascular status with Doppler ultrasound and ankle-brachial blood pressure indices. These measurements, in conjunction with other findings from the history and physical examination, may enable clinicians to stratify patients based on risk and help determine the type of intervention. Other effective clinical interventions may include patient education, optimizing glycemic control, smoking cessation, and diligent foot care. Recent technological advanced combined with better understanding of the wound healing process have resulted in a myriad of advanced wound healing modalities in the treatment of diabetic foot ulcers. However, it is imperative to remember the fundamental basics in the healing of diabetic foot ulcers: adequate perfusion, debridement, infection control, and pressure mitigation. Early recognition of the etiological factors along with prompt management of diabetic foot ulcers is essential for successful outcome.
diabetes; ulcer; prevention; infection; amputation