Osteoporosis treatment and fracture incidence: the ICARO longitudinal study.
None of the available osteoporosis therapies completely abolish the risk of fracture. Among 862 patients on treatment with antiresorptive agents (alendronate, risedronate, and raloxifene) for >1 year a fragility fracture was observed in 9.5%/year. This incidence is considerably higher than that observed in randomized clinical trials.


BACKGROUND
Available osteoporosis therapies reduced in randomized controlled trials (RCTs) the risk of fracture by 30-50%. The proportion of patients suffering from new fractures while on active treatment ("inadequate clinical treatment response" or ICR) can be derived from the data of the RCTs, where confounding factors are usually controlled by the exclusion criteria. In the retrospective part of the ICARO study we observed a 8.9% annual incidence of ICR. Here we report the results of the longitudinal part of the study.


METHODS
The study includes 862 women with severe postmenopausal osteoporosis. Ninety-two of these patients (10.7%) were defined as having ICR (9.5%/year) during therapy with antiresorptive drugs (alendronate, risedronate, and raloxifene) for at least 1 year.


RESULTS
The ICR patients were comparable to patients who did not sustain clinical fractures with regard to body mass index, follow-up duration, number of prevalent vertebral fractures, type of osteoporosis treatment, proportion of patients taking calcium and vitamin D supplements, and compliance with treatment. Those with ICR were significantly older (p=0.032) and more frequently had multiple vertebral deformities (p=0.013).


CONCLUSIONS
The incidence of ICR during treatment with antiresorptive agents among patients with severe postmenopausal osteoporosis in a routine setting is considerably higher than that observed in randomized clinical trials.
Adami
S
S
Rheumatology Department, University of Verona, Valeggio Sul Mincio Hospital (VR), 37067 Valeggio S/Mincio, Verona, Italy. silvano.adami@univr.it
Isaia
G
G
Luisetto
G
G
Minisola
S
S
Sinigaglia
L
L
Silvestri
S
S
Agnusdei
D
D
Gentilella
R
R
Nuti
R
R
D000328:Adult; D000367:Age Factors; D000368:Aged; D019386:Alendronate / Q000627:therapeutic use; D015992:Body Mass Index; D050071:Bone Density Conservation Agents / Q000627:therapeutic use*; D012968:Etidronic Acid / Q000031:analogs & derivatives / Q000627:therapeutic use; D005260:Female; D050723:Fractures, Bone / Q000453:epidemiology / Q000209:etiology* / Q000517:prevention & control; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008137:Longitudinal Studies; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000150:complications* / Q000188:drug therapy* / Q000453:epidemiology; D020849:Raloxifene Hydrochloride / Q000627:therapeutic use; D000068296:Risedronic Acid; D017211:Treatment Failure
D050071:Bone Density Conservation Agents; D020849:Raloxifene Hydrochloride; D000068296:Risedronic Acid; D012968:Etidronic Acid; D019386:Alendronate