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Biomedical subjects

Anna M Sawka

Publications and source records attributed to Anna M Sawka.

17 recordsLinked to original sources
PubMed2006

What is the number of older Canadians needed to screen by measurement of bone density to detect an undiagnosed case of osteoporosis? a population-based study from CaMos.

Routine bone mineral densitometry (BMD) screening has been recommended for women aged >or=65 yr (Osteoporosis Canada [OC], International Society for Clinical Densitometry [ISCD], Canadian and United States Task Forces on Preventative Healthcare, and National Osteoporosis Foundation) and for men >or=65 yr (OC) or >or=70 yr (ISCD). We estimated the number of older Canadians needed to screen (NNS) by BMD to detect an undiagnosed case of osteoporosis, using prospective, multicenter, population-based data from the Canadian Multicentre Osteoporosis Study (CaMos). We included participants aged >or=65 yr with baseline dual-energy X-ray absorptiometry (DXA) BMDs at the femoral neck and lumbar spine (L1-L4). Osteoporosis was defined by a T-score or=65 yr. The percentage prevalence and 95% confidence intervals were determined. In individuals aged >or=65 yr, the prevalence of osteoporosis was 25.6% in women (95% confidence interval, 24.0%, 27.3%) and 8.9% in men (7.3%, 10.8%). In 652 men aged >or=70 yr, the prevalence of osteoporosis was 11.3% (9.1%, 14.0%). Of the participants with BMD-defined osteoporosis, 76.6% of woman aged >or=65 yr (73.2%, 79.6%; 516 of 674 women), 93.4% of men aged >or=65 yr (86.4%, 96.9%; 85 of 91), and 93.2% of men >or=70 yr (84.9%, 97.0%; 68 of 73) were not aware of it. Thus, the minimum NNS by BMD testing to detect one previously undiagnosed case of osteoporosis in Canada is: 6 women aged >or=65 yr, 13 men aged >or=65 yr, and 10 men aged >or=70 yr.

Absorptiometry, Photon↗
PubMed2005

Does alendronate reduce the risk of fracture in men? A meta-analysis incorporating prior knowledge of anti-fracture efficacy in women.

BACKGROUND: Alendronate has been found to reduce the risk of fractures in postmenopausal women as demonstrated in multiple randomized controlled trials enrolling thousands of women. Yet there is a paucity of such randomized controlled trials in osteoporotic men. Our objective was to systematically review the anti-fracture efficacy of alendronate in men with low bone mass or with a history of prevalent fracture(s) and incorporate prior knowledge of alendronate efficacy in women in the analysis. METHODS: We examined randomized controlled trials in men comparing the anti-fracture efficacy of alendronate to placebo or calcium or vitamin D, or any combination of these. Studies of men with secondary causes of osteoporosis other than hypogonadism were excluded. We searched the following electronic databases (without language restrictions) for potentially relevant citations: Medline, Medline in Process (1966-May 24/2004), and Embase (1996-2004). We also contacted the manufacturer of the drug in search of other relevant trials. Two reviewers independently identified two trials (including 375 men), which met all inclusion criteria. Data were abstracted by one reviewer and checked by another. Results of the male trials were pooled using Bayesian random effects models, incorporating prior information of anti-fracture efficacy from meta-analyses of women. RESULTS: The odds ratios of incident fractures in men (with 95% credibility intervals) with alendronate (10 mg daily) were: vertebral fractures, 0.44 (0.23, 0.83) and non-vertebral fractures, 0.60 (0.29, 1.44). CONCLUSION: In conclusion, alendronate decreases the risk of vertebral fractures in men at risk. There is currently insufficient evidence of a statistically significant reduction of non-vertebral fractures, but the paucity of trials in men limit the statistical power to detect such an effect.

Adult↗
PubMed2005

Do hip protectors decrease the risk of hip fracture in institutional and community-dwelling elderly? A systematic review and meta-analysis of randomized controlled trials.

Hip fractures are an important cause of morbidity and mortality in the elderly. Hip protectors are padded undergarments designed to decrease the impact of a fall on the hip. We systematically reviewed randomized controlled trials of hip protectors to determine if they reduce hip fractures in the elderly. Analyses were pooled according to participant residence--community or institutional (the latter, included nursing homes, residential group homes or seniors' hostels). We included individually randomized and statistically adjusted cluster randomized trials. Seven trials of 12- to 28-month duration were included. The Safehip brand of hip protector was used in most studies. Compliance rates in the treatment groups varied from 31 to 68%. In four trials including a total of 5,696 community-dwelling seniors, the hip fracture rates in control groups ranged from 1.1 to 7.4%, and the pooled risk difference with hip protector allocation was 0% [95% confidence intervals (CI), -1%, +1%), with a relative risk of 1.07 (0.81, 1.42). In three trials including 1,188 institutionalized elderly participants, hip fracture rates in the control groups varied from 8 to 19.4%, and the pooled risk difference for sustaining one or more hip fractures with hip protector allocation was -3.7% (95% CI, -7.4%, 0.1%), with a relative risk of 0.56 (0.31, 1.01) (with statistically significant heterogeneity of treatment effect). In a post-hoc subgroup analysis of two trials comprised of exclusively nursing home residents, the risk difference with hip protector allocation was -4.4% (-8.09, -0.76) with a relative risk of 0.50 (0.28, 0.91) (n=1,014). Thus, there is little evidence to support the use of hip protectors outside the nursing home setting. The potential benefit of hip protectors in reducing hip fractures in nursing home residents requires further confirmation.

Activities of Daily Living↗
PubMed2005

Measurement of fractionated plasma metanephrines for exclusion of pheochromocytoma: Can specificity be improved by adjustment for age?

BACKGROUND: Biochemical testing for pheochromocytoma by measurement of fractionated plasma metanephrines is limited by false positive rates of up to 18% in people without known genetic predisposition to the disease. The plasma normetanephrine fraction is responsible for most false positives and plasma normetanephrine increases with age. The objective of this study was to determine if we could improve the specificity of fractionated plasma measurements, by statistically adjusting for age. METHODS: An age-adjusted metanephrine score was derived using logistic regression from 343 subjects (including 33 people with pheochromocytoma) who underwent fractionated plasma metanephrine measurements as part of investigations for suspected pheochromocytoma at Mayo Clinic Rochester (derivation set). The performance of the age-adjusted score was validated in a dataset of 158 subjects (including patients 23 with pheochromocytoma) that underwent measurements of fractionated plasma metanephrines at Mayo Clinic the following year (validation dataset). None of the participants in the validation dataset had known genetic predisposition to pheochromocytoma. RESULTS: The sensitivity of the age-adjusted metanephrine score was the same as that of traditional interpretation of fractionated plasma metanephrine measurements, yielding a sensitivity of 100% (23/23, 95% confidence interval [CI] 85.7%, 100%). However, the false positive rate with traditional interpretation of fractionated plasma metanephrine measurements was 16.3% (22/135, 95% CI, 11.0%, 23.4%) and that of the age-adjusted score was significantly lower at 3.0% (4/135, 95% CI, 1.2%, 7.4%) (p < 0.001 using McNemar's test). CONCLUSION: An adjustment for age in the interpretation of results of fractionated plasma metanephrines may significantly decrease false positives when using this test to exclude sporadic pheochromocytoma. Such improvements in false positive rate may result in savings of expenditures related to confirmatory imaging.

Journal Article↗
PubMed2005

Are oral bisphosphonates effective in improving lumbar bone mineral density in breast cancer survivors with osteopenia or osteoporosis?

OBJECTIVE: Breast cancer survivors with osteoporosis or osteopenia are commonly encountered in primary care and gynaecology practices. Our objective was to determine whether treatment with oral bisphosphonates (alendronate or cyclic etidronate) was more effective than calcium with vitamin D in improving lumbar spine bone mineral density (BMD) within one year in breast cancer survivors. METHODS: Breast cancer survivors with at least one year of clinical follow-up were identified from the prospective observational Canadian Database of Osteoporosis and Osteopenia (CANDOO). Analysis of covariance was used to examine the effects of bisphosphonate therapy on change in lumbar spine BMD at one year compared with the effects of calcium with vitamin D (analysis adjusted for baseline L2-L4 BMD, current tamoxifen use, number of prevalent vertebral fractures [VFs], and time since diagnosis of breast cancer, and age). RESULTS: Eighteen patients took calcium and vitamin D, 25 took cyclic etidronate, and 27 took oral alendronate. Adjusted one-year BMD increases for alendronate and cyclic etidronate compared to calcium and vitamin D were as follows: alendronate 4.53% (95% confidence interval [CI] 1.26%, 7.81%, P = 0.008), and cyclic etidronate 1.85% (-1.55%, 5.25%, P = 0.280). BMD increases were significantly greater in patients with prevalent VF compared to those without VF (P = 0.025). In contrast, time since diagnosis of breast cancer was significantly associated with a decrease in BMD (P = 0.002). We were unable to detect any effect of current tamoxifen use, baseline lumbar spine BMD, or age on changes in BMD at one year. CONCLUSION: Treatment with alendronate was associated with significantly greater improvements in lumbar spine BMD within one year in breast cancer survivors when compared with treatment with cyclic etidronate or calcium and vitamin D.

Aged↗
PubMed2005

A systematic review of the effect of alendronate on bone mineral density in men.

Alendronate is known to increase bone mineral density (BMD) at the lumbar spine and hip in women, but less information is available in men. We conducted a systematic review of randomized controlled trials to determine whether oral alendronate improves BMD at the lumbar spine and hip in men with low bone mass or prevalent fractures, compared with men treated with placebo, calcium, or vitamin D. In three trials in men, BMD (measured by dual-energy X-ray absorptiometry) increased at 2-3 yr (compared to baseline) at the lumbar spine and femoral neck in alendronate-treated patients compared to controls. The pooled estimates of changes in BMD with 10 mg of alendronate daily compared to controls were as follows: 7.8% over 2-3 yr (95% confidence interval [CI] = 4.8- 10.8) at the lumbar spine and 3.8% (95% CI = 2.3-5.3) at the femoral neck (p < 0.001 for treatment effect in each analysis). Statistically significant heterogeneity of treatment effect was noted between trials. We conclude that 10 mg of oral daily alendronate is significantly associated with increase in BMD at the lumbar spine and hip in men over 2-3 yr and that these changes are similar to those previously observed in postmenopausal women.

Alendronate↗
PubMed2004

A systematic review of the literature examining the diagnostic efficacy of measurement of fractionated plasma free metanephrines in the biochemical diagnosis of pheochromocytoma.

BACKGROUND: Fractionated plasma metanephrine measurements are commonly used in biochemical testing in search of pheochromocytoma. METHODS: We aimed to critically appraise the diagnostic efficacy of fractionated plasma free metanephrine measurements in detecting pheochromocytoma. Nine electronic databases, meeting abstracts, and the Science Citation Index were searched and supplemented with previously unpublished data. Methodologic and reporting quality was independently assessed by two endocrinologists using a checklist developed by the Standards for Reporting of Diagnostic Studies Accuracy Group and data were independently abstracted. RESULTS: Limitations in methodologic quality were noted in all studies. In all subjects (including those with genetic predisposition): the sensitivities for detection of pheochromocytoma were 96%-100% (95% CI ranged from 82% to 100%), whereas the specificities were 85%-100% (95% CI ranged from 78% to 100%). Statistical heterogeneity was noted upon pooling positive likelihood ratios when those with predisposition to disease were included (p < 0.001). However, upon pooling the positive or negative likelihood ratios for patients with sporadic pheochromocytoma (n = 191) or those at risk for sporadic pheochromocytoma (n = 718), no statistical heterogeneity was noted (p = 0.4). For sporadic subjects, the pooled positive likelihood ratio was 5.77 (95% CI = 4.90, 6.81) and the pooled negative likelihood ratio was 0.02 (95% CI = 0.01, 0.07). CONCLUSION: Negative plasma fractionated free metanephrine measurements are effective in ruling out pheochromocytoma. However, a positive test result only moderately increases suspicion of disease, particularly when screening for sporadic pheochromocytoma.

Journal Article↗
PubMed2004

Attitudes of women who are currently using or recently stopped estrogen replacement therapy with or without progestins: results of the AWARE survey.

OBJECTIVE: To examine the level of awareness of the findings of the Women's Health Initiative (WHI) study among recent users of hormone therapy (HT). METHODS: A survey was conducted on Canadian women older than 45 years of age who had used either an oral, topical, or vaginal HT within the preceding 3 years. Questionnaires were mailed to a random sample of 210 eligible women within an academic subspecialty rheumatology/osteoporosis practice between April and June 2003. Questionnaires were also provided upon request to women attending tertiary care multidisciplinary clinics and 6 community pharmacies in Hamilton, Ontario. The 98 questions in the survey were either categorical in nature (yes or no response) or followed by a Likert scale. Using chi-square and Student t tests, the responses of women who used combination estrogen/progestin were compared to those who used estrogen alone. RESULTS: Of the 161 women who responded to the survey (128 from the osteoporosis practice, 33 from other clinics and pharmacies), 102 (63%) had used HT for more than 5 years. Ninety-one of 159 respondents (57%) discontinued HT, and 63% (57/91) of those stopped using HT after publication of the WHI principal findings. Sixty-four percent (33/52) of women on combination estrogen/progestin discontinued HT, compared to 50% (46/93) who were on estrogen only, and 5 other women who also discontinued HT but did not know what type of preparation they had been taking (P = .04 for the difference in rates between the 3 groups). Knowledge of the findings of the estrogen/progestin arm of the WHI study did not significantly differ among users of different types of hormone preparations. Of the women who indicated that they did not know if HT affected the risk of WHI-studied medical conditions, 44% (69/156) indicated being unaware of HT risks for stroke, 28% (44/157) for hip fracture, 39% (60/155) for myocardial infarction, 25% (39/155) for breast cancer, and 48% (73/152) for blood clots. Women who had recently taken HT generally did not regret their use of HT. CONCLUSION: Although many women discontinued HT following the publication of the principal findings of the estrogen/progestin arm of the WHI study, the majority of these women lacked a clear understanding of those findings.

Estrogen Replacement Therapy↗
PubMed2004

The economic implications of three biochemical screening algorithms for pheochromocytoma.

Pheochromocytoma is a rare, life-threatening condition. Using a modeling technique, we studied the economic implications of detection strategies for pheochromocytoma (third-party payer perspective). The diagnostic efficacy of biochemical tests was based on Mayo Clinic Rochester data. In all hypothetical algorithms, positive biochemical tests were followed by abdominal computerized tomography and, if negative, metaiodobenzylguanidine scintigraphy. In each hypothetical algorithm, imaging would be indicated after positive biochemical testing as follows: algorithm A, fractionated plasma metanephrine measurements above the laboratory reference range; or algorithm B, abnormal measurements of 24-h urinary total metanephrines or catecholamines. In algorithm C, subjects with fractions of plasma metanephrine at or above 0.5 nmol/liter or normetanephrine at or above 1.80 nmol/liter would undergo imaging, whereas those with values between the reference range and these cutoffs would undergo 24-h urinary measurements (total metanephrines and fractionated catecholamines) and be imaged if positive. We determined that, if 100,000 hypertensive patients (including 500 patients with pheochromocytoma) were tested, algorithm A (measurement of fractionated plasma metanephrines alone) would detect 489 pheochromocytoma patients at a cost of 56.6 million dollars, whereas B (24-h urinary measurements) would detect 457 pheochromocytoma patients for 39.5 million dollars, and C (combination of measurements of fractionated plasma metanephrines and urines) would detect 478 patients for 28.6 million dollars. None of the screening strategies for pheochromocytoma described are affordable if implemented on a routine basis in extremely low-risk patients. However, algorithm C may be the least costly, and at a reasonable level of sensitivity, for subjects in whom the suspicion of disease is moderate.

Adrenal Gland Neoplasms↗
PubMed2004

Clinical review 170: A systematic review and metaanalysis of the effectiveness of radioactive iodine remnant ablation for well-differentiated thyroid cancer.

Radioactive iodine remnant ablation destroys residual thyroid tissue after surgical resection of papillary or follicular thyroid cancer. We systematically reviewed 1543 English references to determine whether remnant ablation decreases the risk of thyroid cancer-related death or recurrence after bilateral thyroidectomy for papillary or follicular thyroid cancer. In 13 cohort studies in which the analysis of thyroid cancer-related outcomes was statistically adjusted to a variable degree for prognostic factors or cointerventions, rates of recurrences of thyroid cancer-related outcomes were significantly decreased in the following: one of seven studies examining thyroid cancer-related mortality, three of six studies examining any tumor recurrence, three of three studies examining locoregional recurrence, and two of three studies examining distant metastases. Thyroid hormone suppressive therapy was not adjusted for in the majority of these analyses. In 18 cohort studies not adjusted for prognostic factors or interventions, the benefit of radioactive iodine ablation in decreasing the thyroid cancer-related mortality and any recurrence at 10 yr was inconsistent among centers. However, pooled analyses were suggestive of a statistically significant treatment effect of ablation for the following 10-yr outcomes: locoregional recurrence (relative risk of 0.31, 95% confidence interval, 0.2, 0.49) and distant metastases (absolute decrease in risk 3%, 95% confidence interval, risk decreases 1-4%). In conclusion, radioactive iodine ablation may be beneficial in decreasing recurrence of well-differentiated thyroid cancer; however, results are inconsistent among centers for some outcomes, and the incremental benefit of remnant ablation in low-risk patients treated with bilateral thyroidectomy and thyroid hormone suppressive therapy is unclear.

Humans↗
PubMed2004

Are there differences between men and women prescribed bisphosphonate therapy in canadian subspecialty osteoporosis practices?

OBJECTIVE: To determine if there are differences between men and women referred for treatment of osteoporosis in Canada. METHODS: We performed an observational study of 1588 patients (163 men, 1425 women), 50 years of age and older, who were prescribed cyclic etidronate or alendronate for treatment of osteoporosis or osteopenia and had at least 2 years of followup registered in the Canadian Database for Osteoporosis and Osteopenia Patients (CANDOO). Comparisons of characteristics between men and women were performed using Pearson chi-square test, Student's t test, or a Kruskal-Wallis test, whichever was most appropriate. RESULTS: Mean baseline femoral neck and lumbar spine bone mineral densities were significantly higher in men than women at both the femoral neck and lumbar spine (p < 0.05, respectively). Men had double the rate of prevalent vertebral fractures (44%, 72/163) compared to women (22%, 315/1425; p < 0.001) and triple the rate of multiple prevalent vertebral fractures (10%, 17/163) compared to women (3%, 37/1425, p < 0.001). Furthermore, men were twice as likely as women to sustain a fracture within 2 years of starting treatment during observation in the CANDOO study (men: 4%, 7/163, women: 2%, 24/1425, p = 0.033). CONCLUSION: Osteoporosis may be under-recognized in men until the condition is at an advanced stage. A form of gender bias may exist in recognition and treatment (or referral for treatment) of osteoporosis in men.

Aged↗
PubMed2003

A comparison of biochemical tests for pheochromocytoma: measurement of fractionated plasma metanephrines compared with the combination of 24-hour urinary metanephrines and catecholamines.

We compared the diagnostic efficacy of fractionated plasma metanephrine measurements to measurements of 24-h urinary total metanephrines and catecholamines in outpatients tested for pheochromocytoma at Mayo Clinic Rochester from January 1, 1999, until November 27, 2000. Catecholaminesecreting tumors were histologically proven. The sensitivity of fractionated plasma metanephrines was 97% (30 of 31 patients), compared with a sensitivity of 90% (28 of 31) for urinary total metanephrines and catecholamines (P = 0.63). The specificity of fractionated plasma metanephrines was 85% (221 of 261), compared with 98% (257 of 261; P < 0.001) for urinary measurements. The likelihood ratios for positive tests were 6.3 (95% confidence interval, 4.7 to 8.5) for fractionated plasma metanephrines and 58.9 (95% confidence interval, 22.1 to 156.9) for urinary total metanephrines and catecholamines. An adrenal pheochromocytoma was missed by urinary testing in two patients with familial syndromes and one asymptomatic patient with an incidentally discovered adrenal mass. An extra-adrenal paraganglioma was missed by plasma testing in one patient. In conclusion, measurements of 24-h urinary total metanephrines and catecholamines yield fewer false-positive results, an attribute preferred for testing low-risk patients, but fractionated plasma metanephrine measurements may be preferred in high-risk patients with familial endocrine syndromes.

Adolescent↗
PubMed2003

What predicts early fracture or bone loss on bisphosphonate therapy?

Factors predicting early fracture or bone loss on bisphosphonate therapy are not well defined. We studied 1588 patients over the age of 50 yr who were started on cyclic etidronate (1119) or alendronate (469) in the CANDOO (Canadian Database for Osteoporosis and Osteopenia Patients) Study. Incident fracture within 2 yr of starting therapy occurred in 31 patients and was independently predicted by a previous history of nonvertebral fracture (odds ratio [OR], 2.98, 95% confidence interval [CI], 1.30, 6.83, p = 0.010). Two hundred and fifty-seven patients lost >/=3% bone mass at the hip or spine (early bone loss) while on bisphosphonate therapy. Protection from early bone loss was most strongly independently predicted by treatment with alendronate with no previous history of etidronate use (OR, 0.29, CI, 0.13, 0.62, p = 0.002). In conclusion, early fracture on bisphosphonate therapy is most strongly predicted by a previous history of fracture and early bone loss is most strongly predicted by the potency of the prescribed bisphosphonate.

Alendronate↗
PubMed2002

Rarity of encephalopathy associated with autoimmune thyroiditis: a case series from Mayo Clinic from 1950 to 1996.

Corticosteroid-responsive encephalopathy associated with autoimmune thyroiditis (also called Hashimoto's encephalopathy) is a rare, life-threatening, treatable, and possibly autoimmune condition. We identified nine patients (with the diagnosis made after 1979) who had relapsing encephalopathy compatible with previous reports of Hashimoto's encephalopathy and no other identifiable cause of encephalopathy at Mayo Clinic Rochester. Of these nine patients, three were clinically hypothyroid, four were subclinically hypothyroid, and two were euthyroid. Thyroid antibodies were positive in eight of eight patients in whom these measurements were made. Electroencephalographic abnormalities were identified in eight of the nine patients (89%). Magnetic resonance imaging (MRI) abnormalities considered etiologically related to encephalopathy were present in three patients (33%). An increased protein concentration was noted on cerebrospinal fluid examination in seven patients (78%). Of the six patients who received high-dose glucocorticoid therapy, 5 (83%) had improvement of neurologic symptoms. In conclusion, encephalopathy associated with autoimmune thyroiditis is rare but important to recognize because it may be responsive to high-dose glucocorticoid therapy. We believe that this condition is not caused by thyroid dysfunction or antithyroid antibodies but represents an association of an uncommon autoimmune encephalopathy with a common autoimmune thyroid disease. The term Hashimoto's encephalopathy is a misnomer and should not be used.

Adolescent↗