Scleroderma prevalence: demographic variations in a population-based sample

OBJECTIVE

To estimate the prevalence of systemic sclerosis (SSc) using population-based administrative data, and to assess the sensitivity of case ascertainment approaches.

METHODS

We ascertained SSc cases from Quebec physician billing and hospitalization databases (covering approximately 7.5 million individuals). Three case definition algorithms were compared, and statistical methods accounting for imperfect case ascertainment were used to estimate SSc prevalence and case ascertainment sensitivity. A hierarchical Bayesian latent class regression model that accounted for possible between-test dependence conditional on disease status estimated the effect of patient characteristics on SSc prevalence and the sensitivity of the 3 ascertainment algorithms.

RESULTS

Accounting for error inherent in both the billing and the hospitalization data, we estimated SSc prevalence in 2003 at 74.4 cases per 100,000 women (95% credible interval [95% CrI] 69.3-79.7) and 13.3 cases per 100,000 men (95% CrI 11.1-16.1). Prevalence was higher for older individuals, particularly in urban women (161.2 cases per 100,000, 95% CrI 148.6-175.0). Prevalence was lowest in young men (in rural areas, as low as 2.8 cases per 100,000, 95% CrI 1.4-4.8). In general, no single algorithm was very sensitive, with point estimates for sensitivity ranging from 20-73%.

CONCLUSION

We found marked differences in SSc prevalence according to age, sex, and region. In general, no single case ascertainment approach was very sensitive for SSc. Therefore, using data from multiple sources, with adjustment for the imperfect nature of each, is an important strategy in population-based studies of SSc and similar conditions.

Mammographically non-calcified ductal carcinoma in situ: sonographic features with pathological correlation in 35 patients

AIM

To present the sonographic findings of mammographically non-calcified ductal carcinoma in situ (DCIS) with histopathologic correlation.

MATERIALS AND METHODS

The mammographic and ultrasonographic presentations of 47 radiographically non-calcified DCIS lesions in 35 patients were retrospectively analysed. Histological characteristics (architectural appearance, nuclear grade, percent of involved lobules, and presence of necrosis) were reviewed.

RESULTS

Seventeen lesions were not mammographically visible (17/47, 36%). Ultrasonographically, these lesions showed an irregular shape (28/47, 60%), microlobulated margins (34/47, 72%) and abrupt interfaces (42/47, 90%). Only 11% (5/47) displayed posterior shadowing. The echotexture of these lesions was most frequently complex (29/47, 62%); therefore, they were divided into two types: type I (24 cases), which were predominantly solid with cystic components, and type II (five cases), which were predominantly cystic with a solid intra-cystic component. A trend to have greater than 50% DCIS cells in cancerous lobules was observed in masses displaying type I echotexture (difference=36%, 95% confidence interval 10.6-62.5) and microlobulated margins (difference=32%, 95% confidence interval 5.1-58.7).

CONCLUSION

Ultrasonographically detected radiographically non-calcified DCIS commonly displays an irregular shape, microlobulated margins, and complex echotexture, giving a "pseudomicrocystic" appearance. Microlobulated margins and "pseudomicrocystic" echotexture seem to be associated with a cancerization of the lobules.

Application of a nomogram for exercise capacity in women with systemic lupus erythematosus

The aim of this study is to examine the exercise capacity in women with systemic lupus erythematosus (SLE). Women with SLE underwent exercise testing; their performance was compared to nomogram predictions. We assessed the potential effects of disease activity and cumulative damage on exercise capacity. We evaluated 52 female SLE patients aged >35 years. The mean workload achieved was somewhat higher than the nomogram predictions. However, over one fifth of the women performed at a very poor level, which in the general population is associated with a twofold increased risk of cardiovascular disease. Compared to other subjects, participants who did poorly tended toward higher disease activity, higher body mass index, and greater smoking prevalence, although the results were not definitive. Exercise testing may be used to identify a subpopulation of lupus patients with a low level of fitness. Extrapolating from general population data, these individuals are likely at particular risk for cardiovascular disease and may, therefore, benefit the most from aggressive cardiovascular risk factor reduction.

Epidermal growth factor receptor-targeted therapy

High epidermal growth factor receptor (EGFR) expression is a feature of human tumours and is an adverse prognostic factor for radiotherapy outcome. High expression is associated with benefit from accelerated radiotherapy in patients with head and neck squamous cell carcinoma. Anti-EGFR strategies potentiate the effects of radiotherapy and the inhibition of deoxyribonucleic acid repair appears to be important amongst a wide range of mechanisms, which include effects on angiogenesis, differentiation and the immunological response. There is considerable interest in exploring combined modality therapies involving radiation and EGFR antagonists for the curative treatment of cancer patients. Important issues in designing new trials are to investigate optimal scheduling and to establish biobanks to develop biomarkers for future patient selection.

Birth of a biome: insights into the assembly and maintenance of the Australian arid zone biota

The integration of phylogenetics, phylogeography and palaeoenvironmental studies is providing major insights into the historical forces that have shaped the Earth's biomes. Yet our present view is biased towards arctic and temperate/tropical forest regions, with very little focus on the extensive arid regions of the planet. The Australian arid zone is one of the largest desert landform systems in the world, with a unique, diverse and relatively well-studied biota. With foci on palaeoenvironmental and molecular data, we here review what is known about the assembly and maintenance of this biome in the context of its physical history, and in comparison with other mesic biomes. Aridification of Australia began in the Mid-Miocene, around 15 million years, but fully arid landforms in central Australia appeared much later, around 1-4 million years. Dated molecular phylogenies of diverse taxa show the deepest divergences of arid-adapted taxa from the Mid-Miocene, consistent with the onset of desiccation. There is evidence of arid-adapted taxa evolving from mesic-adapted ancestors, and also of speciation within the arid zone. There is no evidence for an increase in speciation rate during the Pleistocene, and most arid-zone species lineages date to the Pliocene or earlier. The last 0.8 million years have seen major fluctuations of the arid zone, with large areas covered by mobile sand dunes during glacial maxima. Some large, vagile taxa show patterns of recent expansion and migration throughout the arid zone, in parallel with the ice sheet-imposed range shifts in Northern Hemisphere taxa. Yet other taxa show high lineage diversity and strong phylogeographical structure, indicating persistence in multiple localised refugia over several glacial maxima. Similar to the Northern Hemisphere, Pleistocene range shifts have produced suture zones, creating the opportunity for diversification and speciation through hybridisation, polyploidy and parthenogenesis. This review highlights the opportunities that development of arid conditions provides for rapid and diverse evolutionary radiations, and re-enforces the emerging view that Pleistocene environmental change can have diverse impacts on genetic structure and diversity in different biomes. There is a clear need for more detailed and targeted phylogeographical studies of Australia's arid biota and we suggest a framework and a set of a priori hypotheses by which to proceed.

SLE patients with renal damage incur higher health care costs

OBJECTIVES

To compare costs and quality of life (QoL) between SLE patients with and without renal damage.

METHODS

Seven hundred and fifteen patients were surveyed semi-annually over 4 yrs on health care use and productivity loss and annually on QoL. Cumulative direct and indirect costs (2006 Canadian dollars) and QoL (average annual change in SF-36) were compared between patients with and without renal damage [Systemic Lupus International Collaborating Clinics/ACR Damage Index (SLICC/ACR DI)] using simultaneous regressions.

RESULTS

At study conclusion, for patients with the renal subscale of the SLICC/ACR DI = 0 (n = 634), 1 (n = 54), 2 (n = 15) and 3 (n = 12), mean 4-yr cumulative direct costs per patient (95% CI) were $20,337 ($18,815, $21,858), $27,869 ($19,230, $36,509), $51,191 ($23,463, $78,919) and $99,544 ($57,102, $141,987), respectively. In a regression where the renal subscale of the SLICC/ACR DI was a single indicator variable, on average (95% CI), each unit increase in renal damage was associated with a 24% (15%, 33%) increase in direct costs. In a regression where each level in the renal subscale was an indicator variable, patients with end-stage renal disease incurred 103% (65%, 141%) higher direct costs than those without renal damage. Cumulative indirect costs and annual change in the SF-36 summary scores did not differ between patients.

CONCLUSIONS

SLE patients with renal damage incurred higher direct costs, but did not experience a poorer QoL. QoL may be more influenced by concurrent renal activity than accumulated renal damage, which can occur at any time and patients may gradually habituate to their compromised health state.

A population-based assessment of systemic lupus erythematosus incidence and prevalence--results and implications of using administrative data for epidemiological studies

OBJECTIVES

To estimate (i) systemic lupus erythematosus (SLE) incidence and prevalence using multiple sources of population-based administrative data; (ii) the sensitivity and specificity of case ascertainment methods; and (iii) variation in performance of each ascertainment approach, according to patient and physician characteristics.

METHODS

We examined the physician billing and hospitalization databases of the province of Quebec (1994-2003) covering all health care beneficiaries (approximately 7.5 million). We compared various approaches to ascertain SLE cases, using information from each database separately or combining sources; we then estimated the sensitivity and specificity of these alternative approaches. We used regression models to determine if sensitivity was independently influenced by patient or physician characteristics.

RESULTS

Using billing data, we calculated SLE incidence at 3.0/100,000 person-years [95% confidence interval (CI) 2.6-3.4]; prevalence was 32.8/100,000 persons, in 2003. Results were similar using hospitalization data. However, only a proportion of prevalent cases were identified as having SLE by both methods. Combining cases from billing and hospitalization data, we found a prevalence of 51/100,000 in 2003. Our latent class regression model estimated a prevalence of 44.7/100,000 (95% CI 37.4-54.7). We found high specificity for SLE diagnoses across all strategies and data sources; sensitivity ranged from 42.1% to 67.6%, and was independently influenced by both patient and physician characteristics.

CONCLUSIONS

In observational studies, particularly with administrative databases, SLE incidence and prevalence estimates differ considerably, according to the approach for case ascertainment. In the absence of gold standards, statistical modelling can provide sensitivity and specificity estimates for different approaches.

The relationship between cancer and medication exposures in systemic lupus erythaematosus: a case-cohort study

OBJECTIVE

To examine if, in systemic lupus erythaematosus (SLE), exposure to immunosuppressive therapy (cyclophosphamide, azathioprine, methotrexate) increases cancer risk.

METHODS

A case-cohort study was performed within a multi-site international SLE cohort; subjects were linked to regional tumour registries to determine cancer cases occurring after entry into the cohort. We calculated the hazard ratio (HR) for cancer after exposure to an immunosuppressive drug, in models that controlled for other medications (anti-malarial drugs, systemic glucocorticoids, non-steroidal anti-inflammatory drugs (NSAIDs), aspirin), smoking, age, sex, race/ethnicity, geographic location, calendar year, SLE duration, and lupus damage scores. In the primary analyses, exposures were treated categorically (ever/never) and as time-dependent.

RESULTS

Results are presented from 246 cancer cases and 538 controls without cancer. The adjusted HR for overall cancer risk after any immunosuppressive drug was 0.82 (95% CI 0.50-1.36). Age > or = 65, and the presence of non-malignancy damage were associated with overall cancer risk. For lung cancer (n = 35 cases), smoking was also a prominent risk factor. When looking at haematological cancers specifically (n = 46 cases), there was a suggestion of an increased risk after immunosuppressive drug exposures, particularly when these were lagged by a period of 5 years (adjusted HR 2.29, 95% CI 1.02-5.15).

CONCLUSIONS

In our SLE sample, age > or = 65, damage, and tobacco exposure were associated with cancer risk. Though immunosuppressive therapy may not be the principal driving factor for overall cancer risk, it may contribute to an increased risk of haematological malignancies. Future studies are in progress to evaluate independent influence of medication exposures and disease activity on risk of malignancy.

Prevalence of Schistosoma japonicum infection among animals in fifty villages of Samar province, the Philippines

In the Philippines, there is a need to understand the contribution of different domestic and wild animals in transmitting Schistosoma japonicum infection to humans better. The current study describes variation in animal S. japonicum prevalence across 50 endemic villages of Samar Province, the Philippines. A total of 50 villages were selected, 25 with predominantly rain-fed farms and 25 with some irrigation system. At least 35 cats, dogs, pigs, and water buffaloes each were randomly selected and 30 rat traps were set in each village. Fecal samples were collected for up to three consecutive days for each species. The Danish Bilharziasis Laboratory method (DBL method) was used to determine S. japonicum infection status. A hierarchical logistic regression model with clustering by village and with adjustment for measurement error of the DBL method was used to estimate the prevalence of infection per village and species. Stool samples were collected from 23.4% (1189), 28.6% (1274), 36.3% (1899), and 49.4% (873) of the censused dogs, cats, pigs, and water buffaloes, respectively, and from 663 rats. The adjusted prevalence of S. japonicum infection varied greatly across villages ranging from 1.6% (95% Bayesian Credible Interval: 0.1%-10.2%) to 86.3% (65.9%-97.8%) for dogs, from 0.1% (0%-2.1%) to 21.7% (4.7%-51.2%) for cats, from 0.01% (0.0%%-1.0%) to 18.4% (7.1%-34.7%) for pigs, from less than 0.1% (0.0%-1.2%) to 72.5% (46.0%-97.4%) for water buffaloes, and from 0.7% (0.0%-9.0%) to 95.4% (77.2%-99.9%) for rats. This is the most comprehensive study of animal S. japonicum infection conducted to date. Our results show that, unlike what has been reported in China, very few water buffaloes were infected whereas rats and dogs show high prevalence proportions of infection. This, combined with significant village-to-village variation in prevalence of S. japonicum infection, suggest possible different transmission dynamics of the infection in the Province of Samar in the Philippines and China.

Hodgkin's lymphoma in systemic lupus erythematosus

OBJECTIVE

In systemic lupus erythematosus (SLE), there is a well-documented increased risk of non-Hodgkin's lymphoma (NHL), but little is known about the risk of Hodgkin's lymphoma (HL). The purpose of our work was to describe the phenomenon of HL in SLE.

METHODS

A multi-site cohort of 9547 SLE subjects was assembled; HL cases were ascertained through cancer registry linkage, and the standardized incidence ratio (SIR) for HL was determined. We also performed a literature search for HL cases in SLE, and compared these with our sample. Finally, we pooled results from our cohort study with two large population-based cohort studies providing SIR estimates for HL in SLE.

RESULTS

Five cases of HL occurred in our SLE cohort during the observation interval, for an SIR of 2.4 (95% CI 0.8, 5.5). The literature review documented 13 HL case reports developing in patients with SLE. A pooled analysis combining our data with the other large cohort studies yielded a standardized incidence ratio of 3.16 (95% CI, 1.63-5.51) for HL in SLE.

CONCLUSIONS

Data suggest that risk in SLE is increased not only for NHL, but also for other malignancies arising from B-lymphocytes, including HL.

Prevalence of and factors associated with glucosamine use in Canada

OBJECTIVE

Glucosamine is commonly used for the treatment of osteoarthritis, and its use is increasing in the general population. The Canadian Multicentre Osteoporosis Study (CaMos) provided an opportunity to examine the prevalence of glucosamine use across age and gender groups, and to assess the factors associated with its use.

METHOD

CaMos is a random, population-based sample of 9423 Canadians. Baseline assessments took place in 1996-1997 and the 5-year follow-up assessments in 2001-2002. The primary outcome of this analysis was glucosamine use at year 5. Prevalence estimates were age- and sex-standardized to the Canadian population. A number of factors potentially associated with glucosamine use were identified from the literature. Multivariable logistic regression was used to identify variables associated with glucosamine use.

RESULTS

At 5 years, complete data were available for 7652 of the original 9423 participants (81.2%). For men, glucosamine use increased from 0.9% to 4.7% (weighted values), and for women, it increased from 1.3% to 8.2%. Glucosamine use was higher among older participants, those living in western Canada, and those with arthritis, back pain, higher calcium intake from supplements, physical activity and prior glucosamine use.

CONCLUSIONS

Glucosamine use increased substantially over 5 years, and its use is associated with a number of factors. Some may use glucosamine to manage pain and symptoms of arthritis and back pain, while others use it as a preventive measure to maintain health.

Mortality in systemic lupus erythematosus

OBJECTIVE

To examine mortality rates in the largest systemic lupus erythematosus (SLE) cohort ever assembled.

METHODS

Our sample was a multisite international SLE cohort (23 centers, 9,547 patients). Deaths were ascertained by vital statistics registry linkage. Standardized mortality ratio (SMR; ratio of deaths observed to deaths expected) estimates were calculated for all deaths and by cause. The effects of sex, age, SLE duration, race, and calendar-year periods were determined.

RESULTS

The overall SMR was 2.4 (95% confidence interval 2.3-2.5). Particularly high mortality was seen for circulatory disease, infections, renal disease, non-Hodgkin's lymphoma, and lung cancer. The highest SMR estimates were seen in patient groups characterized by female sex, younger age, SLE duration <1 year, or black/African American race. There was a dramatic decrease in total SMR estimates across calendar-year periods, which was demonstrable for specific causes including death due to infections and death due to renal disorders. However, the SMR due to circulatory diseases tended to increase slightly from the 1970s to the year 2001.

CONCLUSION

Our data from a very large multicenter international cohort emphasize what has been demonstrated previously in smaller samples. These results highlight the increased mortality rate in SLE patients compared with the general population, and they suggest particular risk associated with female sex, younger age, shorter SLE duration, and black/African American race. The risk for certain types of deaths, primarily related to lupus activity (such as renal disease), has decreased over time, while the risk for deaths due to circulatory disease does not appear to have diminished.

The persistence of anticardiolipin antibodies is associated with an increased risk of the presence of lupus anticoagulant and anti-beta2-glycoprotein I antibodies

OBJECTIVE

We studied antiphospholipid antibodies (aPL) in blood samples from a cohort of individuals followed for thrombosis to determine whether the persistent presence of anticardiolipin antibodies (aCL) is associated with a greater likelihood of having lupus anticoagulant and/or anti-beta2-glycoprotein I antibodies (LA/abeta2GPI).

METHODS

Blood samples from 353 individuals who had been tested for aCL on at least two occasions were tested for abeta2GPI and LA. Two groups were defined: aCL-persistent, who tested aCL-positive on at least two occasions, and aCL non-persistent, who tested aCL-positive on fewer than two occasions. Multivariate logistic regressions were performed using LA/abeta2GPI, LA and abeta2GPI as outcome variables and the percentage of aCL-positive tests as the predictor variable, adjusted for age, gender, family history of cardiovascular disease (CVD), systemic lupus erythematosus (SLE), smoking and number of venous (VT) and arterial thromboses (AT).

RESULTS

Sixty-eight (19%) individuals were aCL persistent and 285 (81%) were aCL non-persistent. LA/abeta2GPI was found in 36 (53%) of the aCL persistent group and 38 (13%) of the aCL non-persistent group. The two groups were similar for age, gender and smoking. Family history of CVD, SLE, VT and AT were more frequent in the aCL persistent group. Multivariate analyses revealed that odds ratios for LA/abeta2GPI, LA and abeta2GPI were 1.34 [95% confidence interval (CI) = 1.22-1.47], 1.36 (95% CI = 1.24-1.50) and 1.47 (95% CI = 1.31-1.65) respectively for each 10% increase in aCL-positive tests vs 0% positive tests.

CONCLUSION

Persistence of aCL positivity is associated with an increased risk of LA/abeta2GPI.

Concurrent comparison of three water contact measurement tools in four endemic villages of the Philippines. The schistosomiasis transmission ecology in the Philippines project (STEP)

BACKGROUND

Schistosomiasis japonica is a chronic helminthic infection contracted through contact with water infested with Schistosoma japonicum. The infection is associated with severe disease and is an important public health concern in Philippines.

OBJECT

To estimate the agreement in the frequency of water contact between bimonthly interviews, self-administered diaries and observations.

METHODS

A total of 286 individuals were followed over either a 4 or a 6 months period. Agreement between direct observation and both the bimonthly and diary methods were estimated.

RESULTS

The agreement between the observation and the bimonthly interview was 71.8% when days without any water contacts were considered, but decreased to 23.3% when only days with at least some water contact were considered. The agreement between the observation and the diary was 78.7% when days without any water contacts were considered and 40.8% when only days with some water contacts were considered.

CONCLUSIONS

Agreement about the degree of water contact is poor between the different measurement tools. This has important implications for future research, since a high degree of measurement error can severely bias any results from studies involving water contact.