Acute phase response after zoledronic acid is associated with long-term effects on white blood cells

Quantitative prediction of postpartum hemorrhage in cesarean section on machine learning

BACKGROUND

Cesarean section-induced postpartum hemorrhage (PPH) potentially causes anemia and hypovolemic shock in pregnant women. Hence, it is helpful for obstetricians and anesthesiologists to prepare pre-emptive prevention when predicting PPH occurrence in advance. However, current works on PPH prediction focus on whether PPH occurs rather than assessing PPH amount. To this end, this work studies quantitative PPH prediction with machine learning (ML).

METHODS

The study cohort in this paper was selected from individuals with PPH who were hospitalized at Shijiazhuang Obstetrics and Gynecology Hospital from 2020 to 2022. In this study cohort, we built a dataset with 6,144 subjects covering clinical parameters, anesthesia operation records, laboratory examination results, and other information in the electronic medical record system. Based on our built dataset, we exploit six different ML models, including logistic regression, linear regression, gradient boosting, XGBoost, multilayer perceptron, and random forest, to automatically predict the amount of bleeding during cesarean section. Eighty percent of the dataset was used as model training, and 20 % was used for verification. Those ML models are constantly verified and improved by root mean squared error(RMSE) and mean absolute error(MAE). Moreover, we also leverage the importance of permutation and partial dependence plot (PDP) to discuss their feasibility.

RESULT

The experiment results show that random forest obtains the highest accuracy for PPH amount prediction compared to other ML methods. Random forest reaches the mean absolute error of 21.7, less than 5.4 % prediction error. It also gains the root mean squared error of 33.75, less than 9.3 % prediction error. On the other hand, the experimental results also disclose indicators that contributed most to PPH prediction, including Ca, hemoglobin, white blood cells, platelets, Na, and K.

CONCLUSION

It effectively predicts the amount of PPH during a cesarean section by ML methods, especially random forest. With the above insight, ML predicting PPH amounts provides early warning for clinicians, thus reducing complications and improving cesarean sections' safety. Furthermore, the importance of ML and permutation, complemented by incorporating PDP, promises to provide clinicians with a transparent indication of individual risk prediction.

Zoledronic acid-induced severe lymphopenia

Although anemia, thrombocytopenia, and mild lymphopenia have been reported in the acute phase response after zoledronic acid, severe lymphopenia has not been reported. This article describes a case of severe lymphopenia following a 5 mg zoledronic acid infusion administered to treat osteoporosis. Zoledronic acid is used to treat osteoporosis, hypercalcemia, Paget's disease, and solid malignancies, including multiple myeloma, breast cancer, and prostate cancer. An acute phase response can be seen in 42% of patients after zoledronic acid treatment. Acute phase response may be accompanied by short-term spontaneously recovered anemia, thrombocytopenia, and severe lymphopenia.

The nanoformula of zoledronic acid and calcium carbonate targets osteoclasts and reverses osteoporosis

Osteoporosis is known as an imbalance in bone catabolism and anabolism. Overactive bone resorption causes bone mass loss and increased incidence of fragility fractures. Antiresorptive drugs are widely used for osteoporosis treatment, and their inhibitory effects on osteoclasts (OCs) have been well established. However, due to the lack of selectivity, their off-target and side effects often bring suffering to patients. Herein, an OCs' microenvironment-responsive nanoplatform HA-MC/CaCO₃/ZOL@PBAE-SA (HMCZP) is developed, consisting of succinic anhydride (SA)-modified poly(β-amino ester) (PBAE) micelle, calcium carbonate shell, minocycline-modified hyaluronic acid (HA-MC) and zoledronic acid (ZOL). Results indicate that HMCZP, as compared with the first-line therapy, could more effectively inhibit the activity of mature OCs and significantly reverse the systemic bone mass loss in ovariectomized mice. In addition, the OCs-targeted capacity of HMCZP makes it therapeutically efficient at sites of severe bone mass loss and allows it to reduce the adverse effects of ZOL, such as acute phase reaction. High-throughput RNA sequencing (RNA-seq) reveals that HMCZP could down-regulate a critical osteoporotic target, tartrate-resistant acid phosphatase (TRAP), as well as other potential therapeutical targets for osteoporosis. These results suggest that an intelligent nanoplatform targeting OCs is a promising strategy for osteoporosis therapy.

Regulation of bone mass in inflammatory diseases

Inflammation is among the major determinants of bone loss in chronic disease and aging. Bone metabolism is radically affected by inflammation with consequent bone loss and increased fracture risk. Various cytokines and mediators are involved in the pathogenesis of bone loss in inflammatory conditions. The present review has the aim of discussing the main pathways involved in the pathogenesis of bone loss in inflammatory diseases, focusing in particular on the Wnt system and its regulators. Literature review of studies published between inception to 2021 on osteoporosis and inflammation was conducted. I will discuss the epidemiology of osteoporosis and fractures in common inflammatory diseases. The molecular basis of bone loss related to inflammation will be discussed as well. Finally, the effects of various anti-inflammatory medications on bone metabolism will be reviewed.

The Use of Oral Amino-Bisphosphonates and Coronavirus Disease 2019 (COVID-19) Outcomes

The determinants of the susceptibility to severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) infection and severe coronavirus disease 2019 (COVID-19) manifestations are yet not fully understood. Amino-bisphosphonates (N-BPs) have anti-inflammatory properties and have been shown to reduce the incidence of lower respiratory infections, cardiovascular events, and cancer. We conducted a population-based retrospective observational cohort study with the primary objective of determining if oral N-BPs treatment can play a role in the susceptibility to development of severe COVID-19. Administrative International Classification of Diseases, Ninth Revision, Clinical ModificationI (ICD-9-CM) and anatomical-therapeutic chemical (ATC) code data, representative of Italian population (9% sample of the overall population), were analyzed. Oral N-BPs (mainly alendronate and risedronate) were included in the analysis, zoledronic acid was excluded because of the low number of patients at risk. Incidence of COVID-19 hospitalization was 12.32 (95% confidence interval [CI], 9.61-15.04) and 11.55 (95% CI, 8.91-14.20), of intensive care unit (ICU) utilization because of COVID-19 was 1.25 (95% CI, 0.38-2.11) and 1.42 (95% CI, 0.49-2.36), and of all-cause death was 4.06 (95% CI, 2.50-5.61) and 3.96 (95% CI, 2.41-5.51) for oral N-BPs users and nonusers, respectively. Sensitivity analyses that excluded patients with prevalent vertebral or hip fragility fractures and without concomitant glucocorticoid treatment yielded similar results. In conclusion, we found that the incidence of COVID-19 hospitalization, intensive care unit (ICU) utilization, and COVID-19 potentially related mortality were similar in N-BPs-treated and nontreated subjects. Similar results were found in N-BPs versus other anti-osteoporotic drugs. We provide real-life data on the safety of oral N-BPs in terms of severe COVID-19 risk on a population-based cohort. Our results do not support the hypothesis that oral N-BPs can prevent COVID-19 infection and/or severe COVID-19; however, they do not seem to increase the risk. © 2021 The Authors. Journal of Bone and Mineral Research published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research (ASBMR).

Effect of Zoledronate on Lower Respiratory Infections in Older Women: Secondary Analysis of a Randomized Controlled Trial

A recent observational study of the incidence of pneumonia in patients with previous hip fractures found that bisphosphonate use reduced pneumonia risk by about one-quarter, in comparisons with those either not receiving osteoporosis treatment or receiving treatment with non-bisphosphonate drugs. Mortality from pneumonia was similarly reduced. It was hypothesized that effects of these drugs on immune or inflammatory function might mediate this effect. We have used the adverse event database from our recent 6-year randomized controlled trial of zoledronate in 2000 women over the age of 65 years, to determine whether a similar effect is observed using this more rigorous study design. Seventy-five women had at least one episode of pneumonia (32 [3.2%] zoledronate, 43 [4.3%] placebo) and 119 women had at least one episode of either pneumonia or a lower respiratory tract infection (57 [5.7%] zoledronate, 62 [6.2%] placebo). There were 93 pneumonia events and 167 pneumonia/lower respiratory infection events. For pneumonia, the hazard ratio associated with randomization to zoledronate was 0.73 (95% confidence interval, 0.46-1.16; P = 0.18) and the rate ratio was 0.69 (0.45, 1.04; P = 0.073). For the composite endpoint of pneumonia or lower respiratory infection, the hazard ratio was 0.90 (0.61, 1.30; P = 0.58) and the rate ratio 0.74 (0.54, 0.997; P = 0.048). The proportion of people with events changed approximately linearly over time in both groups, suggesting a progressive divergence in cumulative incidence during the study. In conclusion, these findings lend support to the hypothesis that bisphosphonate use reduces the number of lower respiratory tract infections in older women, though the present study is under-powered for this endpoint and the findings are of borderline statistical significance. Further analysis of other trials of bisphosphonates is necessary to test this possibility further, and exploration of the possible underlying mechanisms is needed.

Investigation of Intravenous Zoledronic Acid Therapy on Circulating Lymphocyte Subpopulation in Patients with Primary Osteoporosis: A Pilot Study

BACKGROUND

Several studies have investigated the immunomodulating properties of zoledronic acid on T lymphocytes, but the causal relationship between the function of T cells and the efficacy of zoledronic acid has not been elucidated.

OBJECTIVE

To investigate the causal relationship between the function of zoledronic acid and T cells.

METHODS

We conducted an observational perspective study to observe the effect of intravenous zoledronic acid once yearly for 2 years on lymphocyte subsets in patients with primary osteoporosis through observing the blood cells analysis and the level of lymphocyte subpopulations before and on day 1, 2, and 3 after first and second administration of intravenous zoledronic acid and bone mineral destiny 1 year after a single administration of zoledronic acid.

RESULTS

White blood cell count and neutrophils increased, whereas lymphocytes and eosinophils decreased after the first and second zoledronic acid infusion. The count of CD3+T cells, CD3+CD4+T cells, and CD16+CD56+ natural killer lymphocytes decreased from day 1 to day 3 after the first and second zoledronic acid infusion, but the results of second infusion showed no significance.

CONCLUSIONS

Further, larger size, more in-depth studies are indicated to examine whether the short-term changes in white blood cells and lymphocyte subtypes noted after 2 once-yearly zoledronic acid injections in this small population of adult patients is associated with the stimulation of immune mechanisms. (Curr Ther Res Clin Exp. 2021; 82:XXX-XXX).

Bisphosphonate-Induced Acute Orbital Inflammation in a Patient With Underlying Thyroid Ophthalmopathy

Bisphosphonates are widely used for various conditions, including osteoporosis, hypercalcemia of malignancy, osteolytic bone metastasis, and Paget's disease. Bisphosphonate-induced orbital inflammation is a rare side effect of amino-bisphosphonates. There has been less focus on the risk of developing amino-bisphosphonate-induced orbitopathy in people who have underlying ophthalmopathy. Herein, we present a case of alendronate-induced acute orbital inflammation in a patient with underlying Graves' ophthalmopathy. Soon after administration of intravenous (IV) dexamethasone with topical prednisolone, the inflammation rapidly resolved. To our knowledge, this is the first case of bisphosphonate-induced orbital inflammation with underlying orbitopathy. This case demonstrates that systemic corticosteroids can be an effective treatment in orbital inflammation in similar cases. There is a possible interaction of T-cell and cytokine involvement mechanisms between Graves' orbitopathy and bisphosphonate-induced orbital inflammation. This case also shows that bisphosphonate-induced acute orbital inflammation is rare but should be part of a physician's differential diagnosis, and more precautions are necessary for patients with underlying orbitopathy who are taking bisphosphonates.

Bisphosphonate-induced orbital inflammation in a patient on chronic immunosuppressive therapy

Background

To report a case of orbital inflammation after bisphosphonate infusion in a patient who was already receiving immunosuppressive therapy.

Case presentation

A 56-year-old woman presented to the ophthalmology clinic with acute onset of right eye pain 24 h after receiving her first Zolendronic acid infusion. She has a past medical history of chronic inflammatory demyelinating polyneuropathy, Sjogren’s syndrome, and systemic lupus erythematosus that have been controlled with immunosuppressive therapy for three years. Clinical ophthalmic exam and MRI studies were significant for right orbital inflammation. The patient was started on oral prednisone with rapid resolution of symptoms.

Conclusions

This is the first case report of a patient receiving chronic immunosuppressive therapy to develop orbital inflammation after Zoledronic acid infusion. In addition, it demonstrates that corticosteroids can be an effective first line therapy in treating orbital inflammation in similar patients. Physicians should be aware of this rare but serious potential side effect of bisphosphonates, and have bisphosphonate-related orbital inflammation on their differential for proper initiation of treatment.

Permanent Discontinuation of Glucocorticoids in Polymyalgia Rheumatica Is Uncommon but May Be Enhanced by Amino Bisphosphonates

OBJECTIVE

The duration of treatment with glucocorticoids (GC) in polymyalgia rheumatica (PMR) is often longterm. Amino bisphosphonates (N-BP) are used in PMR for the prevention of GC-induced osteoporosis, but they coulsd also have immunomodulatory properties. Whether they can be effective as an adjuvant treatment in PMR is unknown. We aimed to establish whether the use of N-BP in our PMR cohort may be associated with GC discontinuation.

METHODS

We conducted a retrospective review of all patients diagnosed with PMR recorded in our electronic medical notes. Cox regression analyses were used to examine the association between the use of N-BP and discontinuation of GC.

RESULTS

Data were retrieved for 385 patients (mean age 71 ± 10 yrs, 64% females, mean initial prednisone dose 19 ± 9 mg/day). The median followup time was 38 months (range 9-57); more than 60% of patients were exposed to N-BP. GC were discontinued in 47% of patients after a median time of 20 months (range 14-27), but subsequently restarted in 39%. Overall, 276/385 patients (72%) were actively treated at their last available evaluation (mean prednisone dose 4.9 ± 5.5 mg/day), while 123/205 (60%) were still receiving GC after 24 months of followup. The use of N-BP was associated with the discontinuation of GC (adjusted HR 0.66, 95% CI 0.50-0.88), independent of age, initial GC dose, and osteoporosis.

CONCLUSION

Unlike current guidelines, longterm treatment with GC is often necessary. These preliminary data suggest that N-BP may be involved in the management of PMR.

Effect of single-dose dexamethasone on acute phase response following zoledronic acid: a randomized controlled trial

Zoledronic acid provokes an inflammatory reaction, or acute phase response, in some individuals. We examined whether treatment with dexamethasone could prevent this response. A single dose of dexamethasone 4 mg, given at the time of zoledronic acid infusion, did not influence the incidence or severity of the acute phase response.

INTRODUCTION

The potent bisphosphonate zoledronic acid (ZOL) is used to treat osteoporosis, Paget's disease, and hypercalcemia of malignancy. This medication can provoke an inflammatory reaction, known as the acute phase response (APR). We examined whether glucocorticoid treatment at the time of first exposure to ZOL prevents the development of APR.

METHODS

This double-blind, randomized, controlled trial assessed 40 adults receiving ZOL 5 mg intravenously for the first time. Participants received oral dexamethasone 4 mg (n = 20) or placebo (n = 20) at the time of ZOL infusion. Oral temperature was measured at baseline and three times a day for 3 days following infusion. Symptoms of APR were assessed via questionnaire at baseline then daily for 3 days and again at day 15 post-infusion. Use of rescue medications (paracetamol or ibuprofen) in the 3 days following infusion was evaluated. Primary outcome was between-group difference in temperature change from baseline.

RESULTS

There was no significant difference in temperature change (p = 0.95) or symptom score (p = 0.42) in the 3 days following ZOL between dexamethasone and placebo recipients. Eleven (55%) in the dexamethasone group and 10 (50%) placebo recipients experienced a temperature increase of ≥1 °C (p = 0.99). Seven (35%) in the dexamethasone group and 9 (45%) in the placebo group experienced an increase in symptom score of ≥3 points (p = 0.75). Thirteen (65%) dexamethasone recipients and 12 (60%) in the placebo group required rescue medications (p = 0.99). Dexamethasone was well-tolerated.

CONCLUSIONS

A single dose of dexamethasone 4 mg does not influence the incidence or severity of APR following first exposure to ZOL.

TRIAL REGISTRATION

ACTRN12615000794505.

Increased CD14+ and decreased CD14- populations of monocytes 48 h after zolendronic acid infusion in breast cancer patients

It has been proposed that bisphosphonates cause osteonecrosis of the jaws through impairment of the monocyte population function and proliferation. Such changes have been confirmed in jaw tissues, ex vivo. In this clinical study, we report for the first time a similar pattern of changes in peripheral blood monocytes.

INTRODUCTION

The aim of this study is to examine the effect of zolendronic acid administration in the peripheral blood white cell population, seeking a plausible pathophysiological link between bisphosphonates and osteonecrosis of the jaw.

METHODS

Twenty-four breast cancer patients, under zolendronic acid treatment for bone metastasis, were included. Peripheral blood samples were obtained prior to and 48 h following zolendronic acid administration. Flow cytometry gated at leukocyte, monocyte, and the granulocyte populations for the CD4/CD8/CD3, CD3/CD16+56/CD45/CD19, CD14/CD123, and CD14/23 stainings were performed.

RESULTS

We were able to record a number of changes in the white cell populations after 48 h of zolendronic acid administration. Most importantly, in the monocyte populations, we were able to detect statistically significant increased populations of CD14+/CD23+ (p = 0.038), CD14+/CD23- (p = 0.028), CD14+/CD123+ (p = 0.070, trend), and CD14+/CD123- (p = 0.043). In contrast, statistically significant decreased populations of CD14-/CD23+ (p = 0.037) and CD14-/CD123+ (p = 0.003) were detected.

CONCLUSIONS

Our results provide evidence supporting the hypothesis that bisphosphonate administration modifies the monocyte-mediated immune response. An increase of CD14+ peripheral blood monocyte (PBMC) populations along with a decrease of CD14- PBMC populations has been recorded. The latter finding is in accordance with limited-currently existing-evidence and warrants further elucidation.

Effectiveness and Safety of Zoledronic Acid in the Treatment of Osteoporosis

The effectiveness of current treatments for osteoporosis is limited by poor patient compliance. However, a favorable dosing regimen of zoledronic acid (ZA) has the potential to improve patient compliance and thus clinical outcomes. The author conducted a retrospective analysis to examine adherence to and the antiosteoporotic effects of a once-yearly infusion of 5 mg of ZA in Taiwanese patients with osteoporosis for up to 48 months. Five men and 149 postmenopausal women (mean age, 77.1 years) were included. Prior to ZA treatment, 66.2% of patients had fractures; most patients discontinued previous treatments due to compliance or convenience issues. Approximately 85% of patients received at least 2 infusions of ZA. Following ZA treatment, bone mineral density improved from baseline at 12 months (11% from baseline; P=.01) and 48 months (20.7% from baseline; P=.009). In addition there was a significant reduction in mean beta-C-telopeptide at all time points from 12 (P<.001) to 36 months (P=.010). New clinical fractures occurred in 16 (10.4%) patients, of which 12 patients experienced a single fracture. Zoledronic acid had an acceptable safety profile; no adverse events were considered to be drug related. Treatment with ZA improved bone health by enhancing bone mineral density and reducing bone turnover, even in high-risk patients. Low fracture rates and high adherence further elucidate the benefits of ZA in the treatment of osteoporosis.

It May Seem Inflammatory, but Some T Cells Are Innately Healing to the Bone

Among the most significant developments to have taken place in osteology over the last few decades is an evolution from treating and viewing bone disorders primarily through an endocrine lens to instead seeing them as metabolic disorders that interface at the molecular and cellular level with the immune system. Osteoimmunology was officially born in response to accumulating evidence that the immune system is integrally involved in bone remodeling, but much of the early work focused on the role of conventional αβ T cells in driving bone loss. There is, however, emerging data indicating that innate lymphocytes, in particular γδ T cells, may in fact be important for bone regeneration. We first observed that bisphosphonate-associated osteonecrosis of the jaw (ONJ), a rare but serious adverse drug effect characterized by nonhealing necrotic bone tissue of the mandible or maxilla, was linked to a deficiency in a subset of γδ T cells found in human peripheral blood. Patients who developed ONJ while on bisphosphonate therapy not only lacked the main subset of circulating γδ T cells, but they also all had underlying conditions that compromised their immune integrity. A number of recent studies have unraveled the role of γδ T cells (and lymphocytes sharing their characteristics) in bone regeneration-particularly for fracture healing. These findings seem to contradict the prevailing view of such "inflammatory" T cells as being bone degenerative rather than restorative. This viewpoint melds together the emerging evidence of these so-called inflammatory T cells in bone remodeling and healing-showing that they are not in fact "all bad to the bone." © 2016 American Society for Bone and Mineral Research.

Management of patients with complex regional pain syndrome type I

Complex regional pain syndrome type I (CRPS-I) includes different conditions characterized by regional pain and sensory, motor, sudomotor, vasomotor, and/or trophic findings, affecting a peripheral limb usually after a noxious event, such as a trauma or surgery. The pathophysiology is still poorly understood. Limited data are available on the incidence of CRPS-I, and the disease is underestimated and under-diagnosed. The disease shows a female preponderance approximately 3:1 with a peak age of incidence around the 5th and 6th decade. The available diagnostic criteria for CRPS-I rely on clinical criteria that are unfortunately focused on the signs and symptoms of the chronic and late disease, while little emphasis is given to the typical imaging (X-rays, bone scintigraphy, MRI) findings of the early phase. Over the last decades, several therapies have been proposed but the few studies available are often too small to be conclusive and rarely evolved to randomized controlled trials (RCTs). On the basis of the results of a few RCTs, only short courses of high bisphosphonate doses appear to provide substantial benefits. The best results are seen in patients in the early phase of the disease, often with the persistent remission or complete healing of the conditions. Since the only accredited mechanism of action of bisphosphonates is the suppression of osteoclastic bone resorption, it is likely the initial dramatic bone loss plays a role in the maintenance and evolution of CRPS-I. Short courses of high doses of bisphosphonates should be considered the treatment of choice for patients with CRPS-I.

Distinct effect of zoledronate and clodronate on circulating levels of DKK1 and sclerostin in women with postmenopausal osteoporosis

The coupling of bone formation to bone resorption during treatment of postmenopausal osteoporosis with antiresorbers might be related to changes in Wnt/b-catenin signaling. We compared the effects of two bisphosphonate treatments on two Wnt-inhibitors Sclerostin (SOST) and Dickkopf-related protein 1 (DKK1). The study population included 74 women with postmenopausal osteoporosis participating simultaneously in two multicenter, placebo controlled trials. The patients were randomized to: intramuscular clodronate 100mg/week (CLO) (N=36), and yearly intravenous therapy with 5mg zoledronate (ZOL) (N=18) and placebo (N=20). Bone turnover markers (intact N-propeptide of type I collagen [P1NP], C-terminal telopeptide of type I collagen [CTX]) remained unchanged in the placebo group while they significantly decreased during treatment with the two bisphosphonates, versus both placebo and baseline. In CLO treated patients serum DKK1 remained stable over the entire period of observation while serum SOST levels increased significantly after 12months of treatment both versus placebo group (p<0,005), baseline (p<0,001) and ZOL treated group. In the ZOL group, DKK1 levels increased significantly within one month and for the following 6months and it fell back to baseline values at 12months. The second ZOL infusion was again associated with an increase in DKK1 a month later, although to a lesser extent. In conclusion, in this study we have found that the treatment of postmenopausal osteoporosis with intermittent yearly ZOL is associated with transient and declining increases in DKK1 while continuous treatment with CLO, results in a late increase in serum SOST. These preliminary results and further ad hoc studies might contribute to shed light on our understanding of the bone coupling effects taking place during treatment of osteoporosis with different anti-resorbers or with different treatment regimens.

Effects of intra-articular clodronate in the treatment of knee osteoarthritis: results of a double-blind, randomized placebo-controlled trial

Aim of this study was to evaluate the efficacy and tolerability of intra-articular (IA) clodronate, compared to saline solution, in patients with symptomatic knee osteoarthritis (KOA). In this double-blind phase 3 randomized clinical trial, patients were randomized to receive once weekly IA injection of 2 mg clodronate or placebo for 4 weeks with 12 weeks of follow-up. The primary objective was the sum of spontaneous, on passive movement, and at digital pressing pain relief assessed by visual analogue score (VAS) of 0-100 at 5 weeks after the final injection. Improving in Western Ontario MacMaster (WOMAC) scale, Lequesne index, consumption of acetaminophen, and physician or patient overall judgment were secondary objectives. Study population included 80 patients, 67 women and 13 men aged 66 ± 6 (SD) years. A significant improvement for all efficacy parameters was observed at all-time points in both groups. A significant difference in favor to clodronate in VAS for pain was observed 5 weeks after the last injection (-114.6 vs. -87.2 for clodronate and placebo group, respectively; p < 0.05). The improvements in Lequesne index, global KOA evaluation from both patients and investigators, and the WOMAC pain subscale were significantly greater in the clodronate group. The proportion of patients that did not require acetaminophen was significantly greater in the clodronate group (about 10 vs. 30 % for clodronate and placebo group, respectively; p < 0.05). IA 2 mg clodronate is associated with small and transient symptomatic and functional benefits and it is safe in KOA patients.