Effect of Methylprednisolone or Zoledronic Acid on Resolution of Active Charcot Neuroarthropathy in Diabetes: A Randomized, Double-Blind, Placebo-Controlled Study

Anti-RANKL Antibody For Active Charcot Foot Neuro-Osteoarthropathy in Patients with Diabetes and Chronic Kidney Disease

BACKGROUND

Charcot neuroosteoarthropathy (CNO) is characterized with increased osteoclastic activity that can be curbed with antiresorptive agents. Chronic kidney disease (CKD) precludes bisphosphonates but anti-receptor activator of nuclear factor-B ligand (anti-RANKL) antibody, denosumab, can be contemplated in CKD. We investigated denosumab for active CNO of foot in CKD for CNO remission.

METHODS

During the study period, 446 persons of diabetes with unilateral, active CNO of foot and CKD were identified and 78 were finally enrolled. Patients received either 60 mg denosumab (single-dose, subcutaneous) along with standard of care (SoC) as total contact cast (TCC) (group A; n = 26) or SoC (group B; n = 52) only. Patients were followed every 4 weeks until CNO remission and subsequently every 8 weeks until 48 weeks following remission. Remission was defined as temperature difference <2 °C between 2 feet confirmed twice (4 weeks apart) with clinical resolution of signs of inflammation. The primary outcome studied was proportion of patients achieving remission within 48 weeks and the time to remission.

RESULTS

Median age was 56.5 (48.8-65) and 57 (48.5-61.2) years, P = .57; duration of diabetes 16 (10-25.3) and 14.9 (10-19) years, P = .151; and estimated glomerular filtration rate 44.8 (21.1-65.6) and 45.7 (32.9-55.7) mL/min/1.73 m2, P = .771, in group A and B, respectively. Median temperature difference at presentation between the affected and opposite foot was 3.4 °C (2.7-6.9) and 3.2 °C (2.2-4.0), P = .119, respectively. All patients achieved remission in group A (100%) compared with 42 (80.8%) in group B (P = .006) (hazard ratio 0.52, 95% CI: 0.32-0.87; P = .012). The median time to remission was similar in the 2 groups (15 [11-25] and 17.5 [14-31.5] weeks, P = .229, respectively). 25-Hydroxyvitamin D3 >14 ng/mL was significantly associated (OR 9.5, 95% CI 1.04-87.5, P = .045) with remission.

CONCLUSION

Anti-RANKL antibody added to SoC (TCC) induces remission of active foot CNO in greater proportions of patients with diabetes and CKD.

Chronic Kidney Disease and Charcot Neuro-Osteoarthropathy of Foot in Diabetes

INTRODUCTION

Charcot neuro-osteoarthropathy (CNO) occurs late in diabetes and may cause fracture, deformity, and higher mortality. Diabetic kidney disease (DKD) affects bone metabolism and contributes to mortality. However, there is no data on prevalence of CNO and its outcomes with coexisting DKD (or chronic kidney disease [CKD]).

METHODS

To ascertain the prevalence of CKD (pick CKD or DKD) among patients with CNO and delineate the remission of active CNO and subsequent lower extremity amputation and all-cause mortality during prospective follow-up. Consecutive patients with diabetic CNO (active or inactive) were enrolled and subsequently divided into those with and without CKD (pick CKD or DKD) (Group A and Group B, respectively). A preestablished timeframe of 36 weeks was utilized to evaluate the remission proportion of active CNO.

RESULTS

A total of 493 CNO patients were observed and 449 subjects (150 patients had active CNO) were further evaluated. The overall prevalence of diabetic nephropathy (DKD or CKD?) CNO was 43.7%. The proportion of patients achieving remission was significantly lower in Group A compared to Group B (OR 0.468, CI [0.239-0.934], P = .025), however, the median time for achieving remission was similar between the 2 groups (14 weeks vs 16 weeks, P = .885). Overall, all-cause mortality was notably higher Group A compared to Group B (OR 2.23, 95% CI [1.474-3.368]) over a median follow-up of 4 years. No significant differences were observed in rates of diabetic foot ulcers (58.2% vs 54.9%; P = .584) and amputations (17.4% vs 15.12%; P = .889) between Group A and Group B.

CONCLUSION

Patients of CNO with coexisting CKD have poor prognosis both in terms of likelihood of active CNO remission and higher mortality.

RANKL-RANK-OPG Pathway in Charcot Diabetic Foot: Pathophysiology and Clinical-Therapeutic Implications

Charcot Foot (CF), part of a broader condition known as Charcot Neuro-Osteoarthropathy (CNO), is characterized by neuropathic arthropathy with a progressive alteration of the foot. CNO is one of the most devastating complications in patients with diabetes mellitus and peripheral neuropathy but can also be caused by neurological or infectious diseases. The pathogenesis is multifactorial; many studies have demonstrated the central role of inflammation and the Receptor Activator of NF-κB ligand (RANKL)-Receptor Activator of NF-κB (RANK)-Osteoprotegerin (OPG) pathway in the acute phase of the disease, resulting in the serum overexpression of RANKL. This overexpression and activation of this signal lead to increased osteoclast activity and osteolysis, which is a prelude to bone destruction. The aim of this narrative review is to analyze this signaling pathway in bone remodeling, and in CF in particular, to highlight its clinical aspects and possible therapeutic implications of targeting drugs at different levels of the pathway. Drugs that act at different levels in this pathway are anti-RANKL monoclonal antibodies (Denosumab), bisphosphonates (BP), and calcitonin. The literature review showed encouraging data on treatment with Denosumab, although in a few studies and in small sample sizes. In contrast, BPs have been re-evaluated in recent years in relation to the high possibility of side effects, while calcitonin has shown little efficacy on CNO.

A randomised feasibility study of serial magnetic resonance imaging to reduce treatment times in Charcot neuroarthropathy in people with diabetes (CADOM)

AIM

This study aims to explore the feasibility of using serial MRI without contrast in the monitoring of Charcot neuroarthropathy to reduce duration of immobilisation of the foot, in order to decide whether a large-scale trial is warranted.

METHODS

A multicentre, randomised, prospective, two arm, open, feasibility study (CADOM) of people with diabetes with a suspected or confirmed diagnosis of Charcot neuroarthropathy. Participants were randomised (1:1) to 'standard care plus', including repeated foot temperature measurements and X-rays, or the intervention arm, with additional three-monthly MRI, until remission of Charcot neuroarthropathy or a maximum 12 months (active phase). Participants were then followed-up for a further 6 months, post remission to monitor for relapse of the Charcot neuroarthropathy (follow-up phase). Feasibility outcomes were recruitment, retention, data completeness, adherence to study procedures and safety of the intervention MRI. We also collected clinical efficacy outcomes, this included time in cast/off-loading device which will be the primary outcome of a future definitive trial. Finally, we collected patient reported outcomes, and data on health and social care usage.

RESULTS

One-hundred and five people were assessed for eligibility at five sites. 64/105 potential participants meet the eligibility criteria to participate in the study. Forty-three participants were randomised: 20 to standard care plus and 23 to MRI intervention. The main reason for ineligibility was a previous episode of Charcot neuroarthropathy. Thirteen participants were withdrawn post-randomisation due to an alternative diagnosis being made. Of the remaining 30 participants, 19 achieved remission, 6 had not gone into remission at the end of the 12 month active phase so exited the study. Five participants were lost to follow-up. Of the MRIs that were not disrupted by COVID-19 pandemic 26/31 (84%) were completed. For the visits that were conducted face-to-face, completion rates of patient-reported outcome measures were between 71 and 100%. There were no safety incidents associated with the intervention MRI. As this was a feasibility study it was not designed to test the effectiveness of serial MRI in diagnosing remission. The time in cast/off-loading device was 235 (±108.3) days for the standard care plus arm compared to 292 (±177.4) days for the intervention arm. There was no statistical difference in the time in cast/off-loading device between the two arms of the study: Hazard Ratio (HR) 0.405 (95% CI 0.140-1.172), p = 0.096.

DISCUSSION

The findings support a definitive randomised controlled trial to evaluate the effectiveness of MRI in diagnosing remission in Charcot neuroarthropathy. The rates of recruitment, retention, data, and MRI completeness show that a definitive study is feasible.

STUDY REGISTRATION

ISRCTN, 74101606 . Registered on 6 November 2017.

Controversies in the management of active Charcot neuroarthropathy

Charcot neuroarthropathy (CN) was first described over 150 years ago. Despite this there remains uncertanity around the factors that contribute to its development, and progression. This article will discuss the current controversies around the pathogenesis, epidemiology, diagnosis, assessment and management of the condition. The exact pathogenesis of CN is not fully understood, and it is likely to be multifactorial, with perhaps currently unknown mechanisms contributing to its development. Further studies are needed to examine opportunities to help screen for and diagnose CN. As a result of many of these factors, the true prevalence of CN is still largely unknown. Almost all of the recommendations for the assessment and treatment of CN are based on low-quality level III and IV evidence. Despite recommendations to offer people with CN nonremovable devices, currently only 40-50% people are treated with this type of device. Evidence is also lacking about the optimal duration of treatment; reported outcomes range from 3 months to more than a year. The reason for this variation is not entirely clear. A lack of standardised definitions for diagnosis, remission and relapse, heterogeneity of populations, different management approaches, monitoring techniques with unknown diagnostic precision and variation in follow-up times prevent meaningful comparison of outcome data. If people can be better supported to manage the emotional and physical consequences of CN, then this could improve people's quality of life and well-being. Finally, we highlight the need for an internationally coordinated approach to research in CN.

Ankle Charcot Mimics: Tubercular Rheumatism to Complex Regional Pain Syndrome

Charcot Foot is often misdiagnosed because of its varied presentation that mimics other common disorders including tubercular rheumatism, complex regional pain syndrome or gout. We present a case of ankle swelling and discuss the differential diagnosis, radiological findings, and management. We also discuss the approach to diagnosis and provide differences in clinical presentations, magnetic resonance imaging,and bone scan findings for various differentials considered for Charcot foot.

Nonoperative Treatment of Charcot Neuro-osteoarthropathy

Conservative treatment of Charcot neuro-osteoarthropathy (CN) aims to retain a stable, plantigrade, and ulcer-free foot, or to prevent progression of an already existing deformity. CN is treated with offloading in a total contact cast as long as CN activity is present. Transition to inactive CN is monitored by the resolution of clinical activity signs and by resolution of bony edema in MRI. Fitting of orthopedic depth insoles, orthopedic shoes, or ankle-foot orthosis should follow immediately after offloading has ended to prevent CN reactivation or ulcer development.

Long-term foot outcomes following differential abatement of inflammation and osteoclastogenesis for active Charcot neuroarthropathy in diabetes mellitus

AIMS

Inflammatory osteolysis is sine-qua-non of active Charcot neuroarthropathy (CN) causing decreased foot bone mineral density (BMD) and fractures. We aimed to explore the effect of anti-inflammatory or anti-resorptive agents for effect on foot bone mineral content (BMC) and consequent long-term outcomes of foot deformities, fractures and amputation.

METHODS

Forty-three patients with active CN (temperature difference >2°C from normal foot) were evaluated. Patients were off-loaded with total contact cast and randomized to receive either methylprednisolone (1gm) (group A), zoledronate (5mg) (group B) or placebo (100ml normal saline) (group C) once monthly infusion for three consecutive months. Change in foot BMC was assessed at 6 months or at remission and followed subsequently up to 4 years for the incidence of new-onset fracture, deformities, or CN recurrence.

RESULTS

Thirty-six participants (24 male, 12 female) were randomized (11 in group A, 12 group B, 13 group C). The mean age was 57.7± 9.9 years, duration of diabetes 12.3± 5.8 years and symptom duration 6.5± 2.8 weeks. BMC increased by 36% with zoledronate (p = 0.02) but reduced by 13% with methylprednisolone (p = 0.03) and 9% (p = 0.09) with placebo at remission. There were no incident foot fractures, however, two patients sustained ulcers, and 3 had new-onset or worsening deformities and none required amputation during 3.36 ± 0.89 years of follow-up.

CONCLUSION

Bisphosphonate for active CN is associated with an increase in foot bone mineral content as compared to decrease with steroids or total contact cast but long-term outcomes of foot deformities, ulceration and amputation are similar.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT03289338.

Effect of Recombinant Human Parathyroid Hormone (1-84) on Resolution of Active Charcot Neuro-osteoarthropathy in Diabetes: A Randomized, Double-Blind, Placebo-Controlled Study

OBJECTIVE

Fractures in Charcot neuro-osteoarthropathy (CN) often fail to heal despite prolonged immobilization with below-knee casting. The aim of the study was to assess the efficacy of recombinant human parathyroid hormone (PTH) in reducing time to resolution of CN and healing of fractures.

RESEARCH DESIGN AND METHODS

People with diabetes and acute (active) Charcot foot were randomized (double-blind) to either full-length PTH (1-84) or placebo therapy, both in addition to below-knee casting and calcium and vitamin D3 supplementation. The primary outcome was resolution of CN, defined as a skin foot temperature difference >2°C at two consecutive monthly visits.

RESULTS

Median time to resolution was 5 months (95% CI 4, 12) in intervention and 6 months (95% CI 2, 9) in control. On univariate mixed Cox and logistic regression, there was no significant difference in time to resolution between the groups (P = 0.64) or in the likelihood of resolution (P = 0.66). The hazard ratio of resolution was 0.84 (95% CI 0.41, 1.74; P = 0.64), and the odds ratio of resolution by 12 months was 0.80 (95% CI 0.3, 2.13; P = 0.66) (intervention vs. control). On linear regression analysis, there were no significant differences in the effect of treatment on fracture scores quantitated on MRI scans (coefficient 0.13 [95% CI -0.62, 0.88]; P = 0.73) and on foot and ankle X-rays (coefficient 0.30 [95% CI -0.03, 0.63]; P = 0.07).

CONCLUSIONS

This double-blind placebo-controlled trial did not reduce time to resolution or enhance fracture healing of CN. There was no added benefit of daily intervention with PTH (1-84) to below-knee casting in achieving earlier resolution of CN.

Efficacy of medical treatment for Charcot neuroarthropathy: a systematic review and meta-analysis of randomized controlled trials

No pharmacotherapeutic agents are yet recommended for active CN though many anti-resorptive agents have been studied. We conducted a systematic review and meta-analysis of the randomized placebo-controlled trials (RCTs) evaluating the time to remission of active CN with anti-resorptive or antiinflammatory drugs. RCTs published in PubMed, EMBASE, SCOPUS and Cochrane Library from January 1994 to December 2019 were accessed. We reviewed studies and extracted information on study design, participants' characteristics, time to remission, bone turnover markers, bone mineral content (BMC) and temperature difference between feet. Five RCTs out of 588 total identified records were included. Standardized mean differences (SMD) between groups with 95% CI are summarized. Pharmacotherapy nonsignificantly increased time to remission [SMD 0.52 weeks (- 0.71, 1.75), p = 0.402; I2 = 88.6%] as compared to TCC alone. The pooled median time to remission with the intervention was 18.5 weeks (11.2, 28.1) compared to 16.8 weeks (8.7, 27.7) with TCC. A nonsignificant increase in BMC [SMD 3.39% (- 0.78, 7.56), p = 0.109; I2 = 96.7%], a decrease in foot temperature [SMD - 0.42 °C (- 0.78, - 0.07), p = 0.020; I2 = 0%] and alkaline phosphatase [SMD = -2.51% (- 3.24, - 1.77), p < 0.001; I2 = 0%] was observed with intervention. Limited evidence from available studies does not support the role of anti-resorptive or anti-inflammatory drugs for earlier remission when added to offloading with total contact cast for active CN of the foot.

An overview of Charcot's neuroarthropathy

Charcot's neuroarthropathy is a destructive complication of the joints, which is often found in people with diabetes with peripheral neuropathy. Despite the fact that its description was published almost 130 years ago, its pathophysiology, diagnosis, and treatment remain areas that need to be described. Thanks to the use of bone remodelling, new therapeutic classes have emerged, we hope that this review will shed light on the pathology from its discovery through to the current state of knowledge on its classification, diagnosis and treatment methods.