MedWire News: N-telopeptide of type I collagen (NTx) and bone alkaline phosphatase (BAP) levels do not seem to differ between patients with diabetes who have osteomyelitis and those who don't, report researchers.
Hilary Babcock (Washington University School of Medicine, USA) and colleagues hypothesized that diabetes patients with osteomyelitis would have an increased bone turnover that would be detected by changes in BAP and NTx.
"Validated biological markers to monitor treatment response and predict treatment outcomes are extremely limited for diabetic foot infections," says the team.
As reported in Diabetes Research and Clinical Practice, the team conducted a matched case-control study of 54 diabetic patients with (n=27) and without (n=27) osteomyelitis who were admitted to Barnes-Jewish hospital from July 2009 to September 2010 for surgery.
The team investigated the association between abnormal bone metabolism and osteomyelitis by comparing BAP and NTx across the groups and assessed the relationship between the bone markers and clinical outcomes in those with osteomyelitis.
Cases of osteomyelitis were defined by the presence of visible or probeable bone underlying a foot ulcer, consistent pathological findings on biopsy, or radiological or intraoperative findings of osteomyelitis.
All individuals not undergoing immediate amputation (n=18) were followed with repeat laboratory measurements after 6 weeks of osteomyelitis treatment and with follow-up phone calls for 6 months to determine if they had further surgery or other problems.
Poor outcome was defined as undergoing further surgery on the affected limb or readmission for osteomyelitis in the same limb within the first 6 months of follow up. All other patients were classified as having favorable outcomes.
The researchers report that no significant differences in BAP or NTx levels were seen between those with and without osteomyelitis at enrollment or follow-up.
In addition, no further significant differences in the bone markers overall were seen between individuals with osteomyelitis with poor versus favorable outcomes at enrollment or follow-up.
"Lack of difference may be due to small sample size, small areas of bone involved in foot osteomyelitis, or limitations of these specific markers," say Babcock et al.
"Pathological changes in bone are slow to present symptomatically or become evident on imaging," say the researchers. "Bone biomarker changes may reflect these underlying changes well in advance and allow clinicians to respond quickly and effectively, allowing bone biomarkers to be used in conjunction with imaging methods."
"Further study of other bone turnover markers in different populations with larger sample size would be helpful," they conclude.
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