Biomedical subjects

James B Semmens

Publications and source records attributed to James B Semmens.

36 records · Page 2Linked to original sources

PubMed2004

Hospital chart review provided more accurate comorbidity information than data from a general practitioner survey or an administrative database.

BACKGROUND AND OBJECTIVE: The accuracy of comorbidity data within the Western Australian Data Linkage System was evaluated by means of comparison with hospital charts and a general practitioner (GP) survey. METHODS: Patients (n=2,037) with a hospital admission from 1991 to 1996 were selected. Linked data were extracted for 100 comorbidities, categorized into 16 diagnostic chapters, for each hospital admission within a 5-year period. Clinical chart review and a GP survey were performed. Comorbidity occurrence in each data source and false-positive and false-negative diagnoses were ascertained. RESULTS: Administrative data contained 45.5% of comorbidity recorded in hospital charts and underascertained secondary conditions for all 16 diagnostic chapters. False-positive diagnoses were low for most conditions (range: 0-1.5%); however, a high occurrence of false negatives existed for all comorbidity chapters (range: 16.3-91.3%). GP-identified comorbidity was 20.0% greater than that found using administrative data but, with the exceptions of injury-poisoning and cutaneous-subcutaneous diseases, was less (42.0%) than that observed from hospital charts. CONCLUSION: Our results indicate that when accurate comorbidity data are crucial to health outcome research, hospital chart review (as opposed to using administrative data) may be required. Furthermore, surveying GPs, at least in Australia, appears an unsatisfactory alternative to hospital charts for obtaining retrospective comorbidity information.

Comorbidity↗

PubMed2004

Significant nonsurgical risk factors for endophthalmitis after cataract surgery: EPSWA fourth report.

PURPOSE: Endophthalmitis remains a devastating complication of cataract surgery, despite improved methods of prophylaxis and surgical technique. The current study was conducted to identify sociodemographic, environmental, and clinical risk factors for the development of postoperative endophthalmitis, using population-based administrative data from Western Australia. METHODS: The Western Australian Data Linkage System identified all patients who underwent cataract surgery, along with those in whom postoperative endophthalmitis subsequently developed, from 1980 to 2000 inclusive. Cases of endophthalmitis were cross-referenced with other sources and validated by medical record review. After selection and preliminary analysis of potential risk factors, multivariate logistic regression modeling was used to estimate odds ratios for the selected variables. RESULTS: Over the 21 years, 210 cases of endophthalmitis occurred after 117,083 cataract procedures, yielding a cumulative incidence rate of 1.79 per 1000 procedures. The incidence of endophthalmitis decreased for extracapsular extraction over the whole period, but not for phacoemulsification over the recent 12 years. There was no risk-adjusted difference in the incidence rate of endophthalmitis for the various cataract surgery procedure types. However, a significantly higher risk was found in patients aged over 80 years, in having surgery in private hospitals, and to a lesser degree in having same-day surgery and surgery in winter. Cataract surgery with lacrimal or eyelid procedures dramatically increased the risk of endophthalmitis. CONCLUSIONS: It may be possible to reduce the incidence rate of postoperative endophthalmitis by almost 80% with a systematic approach to the management of elderly patients, hospital stay, and clinical protocols.

Age Factors↗

PubMed2003

Long-term relative survival in elderly patients after carotid endarterectomy: a population-based study.

BACKGROUND AND PURPOSE: Octogenarians were not included in the major trials of carotid endarterectomy. Concern has been expressed about the role of carotid endarterectomy in this age group. This concern is based in part on uncertainty about the long-term survival of elderly patients after carotid endarterectomy. The aim of the present study was to assess relative survival in those patients >or=80 years of age undergoing carotid endarterectomy. METHODS: A population-based record linkage study of all patients who underwent carotid endarterectomy from 1988 to 1998 in Western Australia was undertaken. Long-term relative survival after carotid endarterectomy was assessed against age- and sex-matched controls. RESULTS: During the period 1988 to 1998, 1796 (1306 male, 490 female) cases were identified. There were 151 patients >or=80 years of age. The cumulative survival at 5 years was 64.9% for those >or=80 years of age compared with 80.1% for those <80 years of age. Relative survival at 5 years was 118% (95% CI, 102 to 134) for those >or=80 years of age compared with 94.7% (95% CI, 92 to 97) for those <80 years of age. CONCLUSIONS: Long-term relative survival after carotid endarterectomy in patients >or=80 years of age was better than that of an age-matched population. The likelihood of living long enough to gain benefit from a carotid endarterectomy is not jeopardized by being too old.

Aged↗

PubMed2003

Circumcision for phimosis and other medical indications in Western Australian boys.

OBJECTIVE: To investigate the incidence rate of circumcision for phimosis and other medically indicated reasons in Western Australian boys from 1 January 1981 to 31 December 1999. DESIGN AND SETTING: A population-based incidence study using hospital discharge data of all circumcisions performed in all WA hospitals during the study period. MAIN OUTCOME MEASURES: Changes in the incidence rate of circumcision for medically indicated reasons. RESULTS: The rate of medically indicated circumcisions increased in boys aged less than 15 years during the study period. Phimosis was the most common medical indication for circumcision in all age groups. The rate of circumcision associated with phimosis was eight times that associated with balanoposthitis and 21 times that of balanitis xerotica obliterans. Boys aged less than five years had the highest rate of circumcision to treat phimosis, at 4.6 per 1000 person-years, representing about 300 circumcisions per year. Boys aged less than five years living in country areas were 1.5 times more likely to be circumcised for phimosis than boys living in metropolitan Perth. CONCLUSION: The rate of circumcision to treat phimosis in boys aged less than 15 years is seven times the expected incidence rate for phimosis. Many boys are circumcised before reaching five years of age, despite phimosis being rare in this age group.

Adolescent↗

PubMed2003

Ovarian cancer in Western Australia (1982-1998): trends in surgical intervention and relative survival.

OBJECTIVES: We aimed to review the utilisation and trends in surgical procedures for the primary management of ovarian cancer and the survival outcomes of patients surgically treated in Western Australia. METHODS: The population-based Western Australia Data Linkage System was used to link hospital morbidity and mortality data for all women diagnosed with malignant primary ovarian cancer in the State Cancer Registry in the period 1982-1998. Poisson regression was used to analyse trends in surgical procedure rates. Logistic regression examined the likelihood of having a surgical procedure in the periods 1988-1993 and 1994-1998 compared with 1982-1987. Relative survival was used to adjust survival estimates for other causes of death occurring in the general female population. RESULTS: There were 1,126 women who underwent a primary surgical procedure for ovarian cancer in Western Australia in the period 1982-1998. Women were more likely to undergo surgery in 1994-1998 (87.8%) compared with 1988-1993 (76.8%), but there was no difference when compared to 1982-1987 (89.2%) (P = 0.62). The likelihood of using specific surgical procedures to treat ovarian cancer increased for all but total abdominal hysterectomy. Bilateral salpingo-oophorectomy was 3.7 times more likely to be performed and omentectomy 5 times more likely to be performed in 1994-1998 compared with 1982-1987. The median length of hospital stay decreased from 15 to 12 days and emergency admissions decreased from 26.5 to 15.4% over the three time periods. Thirty-two percent of women were readmitted within 30 days of separation from their primary surgery, 23% of which were for the same-day treatment with either chemotherapy or radiotherapy. A 15% increase in relative survival was observed between the periods 1982-1997 (38.8%) and 1994-1998 (53.5%).Conclusion. CONCLUSION: Surgery remains a cornerstone in the primary management of ovarian cancer. There have been dramatic shifts in surgical practice in Western Australia, with more women undergoing certain surgical procedures today than they were 20 years ago. Coupling the increasing surgical trends are improved outcomes. Fewer women are presenting as an emergency, the length of hospital stay has been reduced, and survival outcomes have shown a significant improvement.

Aged↗

PubMed2003

Trends in cataract surgery and postoperative endophthalmitis in Western Australia (1980-1998): the Endophthalmitis Population Study of Western Australia.

OBJECTIVES: Postoperative endophthalmitis results from an intraocular infection and usually occurs following cataract surgery. It has significant morbidity and causes severe visual impairment or blindness of the eye. The aim of this study was to assess the trends in the incidence rates of cataract surgery and postoperative endophthalmitis in Western Australia for the period 1980-1998. METHODS: The Western Australian Record Linkage Project was used to link the morbidity records for all patients treated for cataract surgery in Western Australia in 1980-1998. Patient records were selected using the international classification for diagnosis and procedure codes pertaining to cataract surgery and postoperative endophthalmitis. All cases of postoperative endophthalmitis were validated by case-note review. The separate databases of the Royal Perth Hospital microbiology and anaesthetic departments as well as the vitreo-retinal surgeon logbooks were used to cross-validate the hospital morbidity database. Trends in the incidence rates of cataract surgery and postoperative endophthalmitis were assessed by Poisson regression. RESULTS: There were 94,653 cataract procedures performed for 63,007 patients in Western Australia during the 19-year period. The majority (88%) of cataract procedures performed were in patients aged 60 years or older. Postoperative endophthalmitis developed in 188 patients, with serious visual impairment occurring in 70.6% of patients for whom visual acuity data was available at presentation. The incidence rate of cataract surgery increased more than three-fold from 1981 (102 per 100,000 person years) to 1998 (345 per 100,000 person years), mainly due to the increase in extracapsular cataract extraction during the 1980s and phacoemulsification extraction from 1990 onwards. In contrast, the average annual incidence rate of postoperative endophthalmitis remained relatively unchanged at around 2 per 1000 cataract procedures over the same period. CONCLUSION: Cataract surgery is becoming more prevalent in the elderly as the life expectancy of the population increases. There has been a dramatic shift in surgical practice during the last 30 years with small-incision phacoemulsification being the predominant method of intervention used since 1990. Despite changes in surgical practice the incidence rate of postoperative endophthalmitis has remained the same.

Aged↗

PubMed2003

Breast cancer and pregnancy: a diagnostic and management dilemma.

BACKGROUND: The purpose of the present paper was to review the current knowledge of pregnancy concurrent with a diagnosis of breast cancer, and how best to manage this group of women and those breast cancer survivors who may subsequently conceive. RESULTS: Pregnancy-associated breast cancer or gestational breast cancer is defined as breast cancer diagnosed during pregnancy or in the 12 months post-partum. A review of the current literature on breast cancer-related pregnancy suggests an incidence of between 0.7 and 3.9%. The prognosis is thought not to be significantly different from non-pregnancy-associated breast cancer, except in cases where a delay in diagnosis is associated with more advanced disease. The treatment is similar to non-pregnant cases, with the exception of radiotherapy, which is contraindicated throughout pregnancy; and chemotherapy, which is contraindicated during the first trimester. Few breast cancer survivors go on to conceive, but those who do have no worse breast cancer or pregnancy outcomes. CONCLUSION: Most of the research in this field has come from small, specialized institutions and may not reflect what occurs in the wider community. Further population-based research in this area is needed, and is currently being undertaken in Western Australia.

Antineoplastic Agents↗

PubMed2003

Routine circumcision practice in Western Australia 1981-1999.

BACKGROUND: Routine neonatal circumcision has declined in most English-speaking countries. The purpose of the present study was to investigate the trends in incidence of routine circumcision in Western Australia and current patterns of the procedure according to sociodemographic factors. METHODS: Hospital morbidity data were used to conduct a population-based study of all circumcisions performed in Western -Australian hospitals during 1981-1999. Medicare insurance rebate statistics were used to estimate the numbers of circumcisions performed outside of hospital on boys <6 months of age between 1994 and 1999. RESULTS: In 1994, 9.8% of boys were circumcised before reaching 6 months of age, falling to 7.9% by 1999. Boys <6 months of age were 3.3 times more likely to undergo a hospital-performed circumcision if they lived in country areas compared with metropolitan Perth. Middle socioeconomic class families were twice as likely to circumcise a son than those in the higher and lower socioeconomic groups. The decreasing circumcision rate in boys <6 months of age was partly offset by an increase in routine circumcisions in boys older than 6 months of age during 1981-1999. CONCLUSION: Circumcision remains a relatively common procedure in Western Australia. Based on total routine circumcision rates in 1999, 10.2% of boys will be circumcised by the time they reach 15 years of age. The routine circumcision rate in boys <6 months is falling in contrast to a rising routine circumcision rate in older boys. Risk factors for a circumcision before 6 months of age include living in country areas and a middle socioeconomic status.

Adolescent↗

PubMed2003

Ovarian cancer in Western Australia (1982-98): incidence, mortality and survival.

OBJECTIVES: To investigate the trends in incidence and mortality and estimate survival for women diagnosed with ovarian cancer in Western Australia. CASE SELECTION AND METHODS: There were 1,336 women diagnosed with ovarian cancer in 1982-98. Age-standardised rates were calculated by the direct method. Age-period and age-cohort models were analysed by Poisson regression. The Kaplan-Meier method was used to estimate survival and Cox proportional hazards regression evaluated the relative risk of dying. RESULTS: Trends in age-adjusted incidence and mortality rates showed little changed over the three time periods of diagnosis. A significant birth cohort effect showed a peak in the risk in the 1924 (mid-year) cohort followed by a general decrease in both incidence and mortality risk. Survival at five years was 34% (95% CI 31.3-36.5) overall, but was only 27% (95% CI 17.4-36.7) among women with stage III and IV disease. Aboriginal women showed a risk of dying twice that of non-Aboriginal women. CONCLUSIONS: The birth cohort analysis of ovarian cancer proved better at explaining disease trends than was time period of diagnosis. Survival continues to be poor, but Aboriginal women and those with serous and unspecified adenocarcinoma tumours fair much worse. IMPLICATIONS: As the leading cause of death from a gynaecological malignancy, ovarian cancer is of public health importance. Historical trends in birth rates and the use of oral contraceptives help to explain at least some of the observed birth cohort trends in this study. In the long term, an effective diagnostic technique needs to be developed or this disease will continue to be diagnosed at an advanced stage when treatment options for cure are limited.

Adult↗

PubMed2003

Suprarenal fixation: effect on blood flow of an endoluminal stent wire across an arterial orifice.

PURPOSE: To investigate what effect, if any, the presence of a stent wire in front of a renal artery has on the volume flow rate of blood through the renal artery. METHODS: Experimental, numerical, and analytical modeling methods were used to test 4 separate stent wire configurations: a stent wire across the center of an artery orifice, an off-center wire placed at one-quarter the arterial diameter, a V-shaped wire with its vertex at the center, and 2 stent wires at one-third-diameter spacing. RESULTS: For all the configurations studied, the presence of stent wires has a minimal effect on the blood flow rate into an artery of >/=3-mm diameter, with most flow rates decreasing by around 1%. This is true provided that there is no buildup of material on the wire. When material buildup was "encouraged" to occur, then decreases in flow rate of up to 40% were observed. The numerical and analytical methods indicated that the flow rates would, in most cases, decrease by around 3% to 10%. CONCLUSIONS: A bare stent wire in front of a >3-mm-diameter artery decreases the flow rate minimally, providing there is no material on the wire. Although the numerical and analytical methods indicated a greater effect on flow, the approximations required for these 2 methods to obtain meaningful solutions suggest that the experimental results are the most accurate. Nonetheless, the analytical equations provided a useful approximation for determining the effect on blood flow due to the presence of a stent wire.

Angioplasty↗

PubMed2003

Endoluminal repair of mycotic thoracic aneurysms.

PURPOSE: To report a series of endoluminally repaired mycotic thoracic aneurysms. CASE REPORTS: Four patients with presumed mycotic aneurysms of the thoracic aorta were treated with endovascular grafts owing to overly high risk for open repair. All aneurysms were successfully excluded at the initial intervention. In one case, which required endograft fenestrations for the superior mesenteric and renal arteries, the patient died 53 days after the procedure, following graft migration and occlusion of major branch vessels. The other 3 patients remain alive and well at a mean follow-up of 16 months with no signs of ongoing sepsis. CONCLUSIONS: Endoluminal repair of thoracic mycotic aneurysms is technically feasible and, in association with long-term antibiotics, offers at least temporary protection against imminent rupture.

Aged↗

PubMed2003

Follow-up after endovascular aortic aneurysm repair: the plain radiograph has an essential role in surveillance.

Periodic follow-up is mandatory for patients with aortic stent-grafts. Central to surveillance is the establishment of a baseline against which changes can be detected. Computed tomography (CT) has been the benchmark of follow-up imaging for endografts, but comparison of serial AP and lateral plain radiographs will detect structural alterations that can be missed on CT scans. In this review, we illustrate these common endograft complications and the value of plain radiographs in their detection. We believe that the plain radiograph should be the cornerstone of aortic endograft surveillance. However, a standardized protocol should be used to avoid parallax and positioning errors that affect interpretation.

Aortic Aneurysm, Abdominal↗

PubMed2003

Retrograde fenestration of endoluminal grafts from target vessels: feasibility, technique, and potential usage.

PURPOSE: To report initial experiments involving a new method for percutaneous intraprocedural stent-graft fenestration from the target vessel. TECHNIQUE: In bench and canine models, the fabric of an implanted Zenith endograft was punctured easily using the stiff end of a coronary 0.014-inch guidewire delivered through the target vessel (e.g., renal or iliac artery). A 20-G cutting needle was passed over the coronary wire to enlarge the puncture site, followed by a cutting balloon to create a fenestration that was of sufficient size to allow deployment of a stent. CONCLUSIONS: In vivo endograft fenestration of a Zenith endograft is feasible. In addition to providing a percutaneous means of intentionally fenestrating a stent-graft from the artery to be perfused, the technique has potential application as a bailout maneuver after inadvertent side branch occlusion. Although the time to achieve successful fenestration in the experimental model was long, refinement may achieve performance times adequate to maintain viability of the end organ.

Animals↗

PubMed2002

The effect of age on serum creatinine levels in an aging population: relevance to vascular surgery.

BACKGROUND AND AIM: Serum creatinine is commonly used to assess and monitor renal function in the management of abdominal aortic aneurysm with endoluminal grafting, and for intervention of renal artery occlusive disease. The majority of patients selected for these procedures are elderly and serum creatinine is used post-operatively to monitor renal function. There is a need to adjust the serum creatinine concentration for age to determine the changes that might be due to the procedure: especially with endoluminal grafting using transrenal manipulation and fixation, and procedures involving interventions directly on the renal arteries. A single reference interval for serum creatinine is usually given for each sex but does not take into account variation due to age. The objective of this study was to establish age related reference intervals for serum creatinine, especially for those over 60 years of age to assist in the clinical interpretation of creatinine levels in the years following endoluminal grafting for aneurysms of the abdominal aorta. METHODS: A pathology services database was established for serum creatinine measurements from 98,688 patients (44,784 males and 53,904 females). Data was stratified into five year age groups and reference intervals assigned for each age group after a reference population was determined. The heterogeneous population was refined firstly by removing patients with extreme (> or =200 micromol/l) concentrations of serum creatinine, outliers and repeated values. Secondly, a putative "healthy" population was determined by removing values outside three standard deviations of the mean. Two statistical methods, the Bhattacharya and Hoffmann methods, were then applied to obtain a putative reference population. Serum creatinine data was obtained from the Busselton Population Research Foundation for comparison. FINDINGS: Serum creatinine concentration increased steadily with age; in females from the age of 40 years and 60 years for males. Reference intervals for males and females aged from 20 to 94 years were established. Advancing age affects serum creatinine levels, especially in the "vascular" age group of 60 to 80 years. The changes in serum creatinine concentration that occur with age is relevant in interpretation of the results of renal monitoring after intervention.

Adult↗

PubMed2002

Complete colonoscopy rarely misses cancer.

BACKGROUND: The assumption that colonoscopy is highly accurate for detecting colorectal cancer was tested by identifying cancer subsequent to colonoscopy in 2 cohorts of patients in which colonoscopy was reported as normal. METHODS: A multicenter endoscopy database was used to identify all reportedly normal colonoscopies. One cohort was assessed 5 years after colonoscopy with the use of a population-based health services-linked database to link patient morbidity, cancer, and mortality data. The second cohort was assessed by identifying patients who had cancer on repeat colonoscopy. RESULTS: Of 1047 patients with normal colonoscopies followed for 5 years or until death if earlier, 5 cancers (0.5%) were detected. This rate was not significantly different from that predicted by Australian statistics (risk = 1.0%, p > 0.1), but significantly lower compared with that for all patients presenting for colonoscopy during the study period (risk = 5.2%, p < 0.001). In another cohort of 8486 patients with reportedly normal colonoscopies, 496 patients underwent repeat colonoscopies during an average follow-up of 3.1 years; cancer was diagnosed at the subsequent procedure in 3 patients (0.6%). CONCLUSIONS: The high accuracy of colonoscopy is demonstrated by the low risk of harboring an advanced neoplastic lesion after a normal examination.

Aged↗

PubMed2002

Trends and outcomes for women diagnosed with ovarian cancer in Australia.

BACKGROUND: Cancer of the ovary is the sixth most common cancer in women and the leading cause of death from a gynaecological malignancy. Early disease is asymptomatic and often results in a late diagnosis with approximately two-thirds of all cases presenting at an advanced stage. OBJECTIVE: To provide an overview of ovarian cancer trends and disease management, and the implications of these for general practice. DISCUSSION: There has been little change in the incidence and mortality of ovarian cancer in the past two decades, despite an increase in the proportion of women receiving surgical treatment to manage the disease. The aetiology of ovarian cancer remains obscure. There is an urgent need for new techniques to be developed that will allow diagnosis to occur at an early stage in the disease process if real improvements in morbidity and mortality outcomes are to be achieved. The general practitioner has an important role in the initial diagnosis of ovarian cancer by assessing female patients' risk of the disease and by making the appropriate referral to a gynaecological oncologist.

Australia↗

PubMedDate not supplied

Socioeconomic and rural differences for cataract surgery in Western Australia.

BACKGROUND: To examine the relationship between socioeconomic factors, residential locality and cataract surgery incidence. METHODS: This was a population-based study using the Western Australian Data Linkage System to identify all cataract operations performed in patients aged 50+ years in 1996 and 2001. Patients' residential addresses at the time of operation were geocoded to census localities. Using census-derived indices, procedures were categorized into socioeconomic groups and residential locations (metropolitan and rural). Poisson regression was used to analyse for differences in procedure rates. RESULTS: The crude cataract surgery rate in Western Australia increased from 4458 to 6631 procedures per million person-years between 1996 and 2001. Female and older patients underwent more surgery. Metropolitan residents were more likely to undergo surgery compared with rural residents; a difference that increased by 17% between 1996 and 2001 (1996: incidence rate ratio [IRR] 1.07, 95% confidence interval [CI] 1.02-1.13; 2001: IRR 1.24, 95% CI 1.18-1.29). A pronounced 'U-shaped' pattern of difference had developed for socioeconomic disadvantage by 2001. The most advantaged underwent 9% more surgery than the most disadvantaged. Rates in the middle two groups were less than the lowest one. CONCLUSION: There was growing inequity in the rates of cataract surgery for rural and poorer patients between 1996 and 2001. These differences partly reflect the increasingly two-tiered Australian health system with more privately provided cataract surgery in urban areas.

Aged↗

PubMedDate not supplied

Experimental force measurements on a bifurcated endoluminal stent graft model: comparison with theory.

The goal of this study was to experimentally validate a steady-state mathematical model, which can be used to compute the forces acting on a bifurcated endoluminal stent graft. To accomplish this task, an acrylic model of a bifurcated graft was used for the force measurements. The graft model was connected to the inlet piping with a flexible rubber membrane that allowed the graft model to move. This allowed us to measure the force owing to the movement of the graft model with a calibrated load cell. Steady-state blood flow was assumed, and the working fluid was water. The experimental data were found to be consistent with the results from a previously published mathematical model: the graft force is strongly dependent on the proximal or inlet pressure and the inlet area. The force tends to be weakly dependent on flow rate. More research work will be required to determine whether the steady-state force model examined in this article provides a realistic determination of the forces on an endoluminal stent graft that is subject to pulsatile blood flow.

Aortic Aneurysm, Abdominal↗