Evaluation of safety and analgesic consumption in patients with advanced cancer treated with zoledronic acid

Methodological Errors in Clinical Studies Published by Medical Journals of Ex-Yugoslav Countries

INTRODUCTION

Certain methodological principles should be inexcusably followed when designing clinical or observational research to avoid bias and presentation of results that do not reflect the truth about the phenomenon that is the object of the study.

AIM

The aim of this study was to compare the methodological quality of clinical trials and observational studies published in medical journals from ex-Yugoslav countries indexed in Pubmed/MEDLINE.

METHODS

Clinical studies published in medical journals of ex-Yugoslav countries were retrieved from the Pubmed/MEDLINE database, and the sample for analysis was randomly chosen from the retrieved publications. The rate of the most common errors in the design of clinical/observational studies was established by a careful reading of the sampled publications and their checking against predefined criteria.

RESULTS

The studies published in two countries that are now member states of the European Union (Slovenia and Croatia) have significantly higher citation rates, impact factor, and methodological quality scores than studies from other ex-Yugoslav countries. While publications from Croatia show clear improvement trend throughout the last two decades, which is visible also in the last 10 years in Slovenia and Bosnia and Herzegovina, quality of clinical research published in journals from Serbia was stagnating in the same period.

CONCLUSIONS

There are significant differences in methodological quality and scientometric characteristics of clinical research published in medical journals of ex-Yugoslav countries that could be mitigated by more intensive training of clinical researchers in statistics and research design, as well as by more rigorous editorial practices.

Hypocalcaemia in patients with prostate cancer treated with a bisphosphonate or denosumab: prevention supports treatment completion

Background

Most patients with advanced prostate cancer develop bone metastases, which often result in painful and debilitating skeletal-related events. Inhibitors of bone resorption, such as bisphosphonates and denosumab, can each reduce the incidence of skeletal-related events and delay the progression of bone pain. However, these agents are associated with an increased risk of hypocalcaemia, which, although often mild and transient, can be serious and life-threatening. Here we provide practical advice on managing the risk of hypocalcaemia in patients with advanced prostate cancer who are receiving treatment with bone resorption inhibitors. Relevant references for this review were identified through searches of PubMed with the search terms ‘prostate cancer’, ‘bone-targeted agents’, ‘anti-resorptive agents’, ‘bisphosphonates’, ‘zoledronic acid’, ‘denosumab’, ‘hypocalcaemia’, and ‘hypocalcemia’. Additional references were suggested by the authors.

Main text

Among patients with advanced cancer receiving a bisphosphonate or denosumab, hypocalcaemia occurs most frequently in those with prostate cancer, although it can occur in patients with any tumour type. Consistent with its greater ability to inhibit bone resorption, denosumab has shown superiority in the prevention of skeletal-related events in patients with bone metastases from solid tumours. Consequently, denosumab is more likely to induce hypocalcaemia than the bisphosphonates. Likewise, various bisphosphonates have differing potencies for the inhibition of bone resorption, and thus the risk of hypocalcaemia varies between different bisphosphonates. Other risk factors for the development of hypocalcaemia include the presence of osteoblastic metastases, vitamin D deficiency, and renal insufficiency. Hypocalcaemia can lead to treatment interruption, but it is both preventable and manageable. Serum calcium concentrations should be measured, and any pre-existing hypocalcaemia should be corrected, before starting treatment with inhibitors of bone resorption. Once treatment has started, concomitant administration of calcium and vitamin D supplements is essential. Calcium concentrations should be monitored during treatment with bisphosphonates or denosumab, particularly in patients at high risk of hypocalcaemia. If hypocalcaemia is diagnosed, patients should receive treatment with calcium and vitamin D.

Conclusion

With preventative strategies and treatment, patients with prostate cancer who are at risk of, or who develop, hypocalcaemia should be able to continue to benefit from treatment with bisphosphonates or denosumab.

Severe resistant hypocalcemia in multiple myeloma after zoledronic acid administration: a case report

Introduction

Hypercalcemia is one of the most common metabolic abnormalities encountered in any form of malignancy. Hypocalcemia, however, is a rare manifestation, especially in cancers with bone involvement. Here we present a case of hypocalcemia in a patient with multiple myeloma that was refractory to treatment.

Case presentation

A 73-year-old African American woman recently diagnosed with multiple myeloma, presented with a 2-day history of fever, vomiting and hypocalcemia. Ten days prior to admission she received zoledronic acid, Velcade^® (bortezomib), Revlimid^® (lenalidomide) and dexamethasone. Treatment was started with intravenous antibiotics and calcium gluconate boluses. After 24 hours of treatment her calcium level became undetectable (<5mg/dL). Continuous intravenous calcium gluconate infusions in addition to boluses were started. She remained persistently hypocalcemic and eventually developed tonic–clonic seizures. Vitamin D levels were found to be low and intravenous paricalcitol was initiated, which improved her calcium level.

Conclusions

Underlying vitamin D deficiency can precipitate severe hypocalcemia in patients with multiple myeloma receiving bisphosphonates. This warrants baseline screening for vitamin D deficiency in these patients.