Authors' reply to "A comment on 'Functional oral-motor skills: Do they change with Age?' (Dysphagia 13:195-201, 1998)"
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Journal Article↗
Biomedical subjects
M Abrahamowicz
Publications and source records attributed to M Abrahamowicz.
Evaluation of rubella screening in pregnant women.
BACKGROUND: The rationale for rubella vaccination in the general population and for screening for rubella in pregnant women is the prevention of congenital rubella syndrome. The objective of this study was to evaluate the effectiveness of the prenatal rubella screening program in Quebec. METHODS: A historical cross-sectional study was designed. Sixteen hospitals with obstetric services were randomly selected, 8 from among the 35 "large" hospitals in the province (500 or more live births/year) and 8 from among the 50 "small" hospitals (fewer than 500 live births/year). A total of 2551 women were randomly selected from all mothers of infants born between Apr. 1, 1993, and Mar. 31, 1994, by means of stratified 2-stage sampling. The proportions of women screened and vaccinated were ascertained from information obtained from the hospital chart, the physician's office and the patient. RESULTS: The overall (adjusted) screening rate was 94.0%. The rates were significantly different between large and small hospitals (94.4% v. 89.6%). Five large hospitals and one small hospital had rates above 95.0%. The likelihood of not having been screened was statistically significantly higher for women who had been pregnant previously than for women pregnant for the first time (4.8% v. 1.4%; p < 0.001). Of the 200 women who were seronegative at the time of screening (8.4%), 79 had been vaccinated postpartum, had a positive serological result on subsequent testing or did not require vaccination, and 59 had not been vaccinated postpartum; for 62, subsequent vaccination status was unknown. INTERPRETATION: Continued improvement in screening practices is needed, especially in small hospitals. Because vaccination rates are unacceptably low, it is crucial that steps be taken to address this issue.
Canada↗
Association between licensing examination scores and resource use and quality of care in primary care practice.
CONTEXT: Clinical competence is a determinant of the quality of care delivered, and may be associated with use of health care resources by primary care physicians. Clinical competence is assumed to be assessed by licensing examinations, yet there is a paucity of information on whether scores achieved predict subsequent practice. OBJECTIVE: To determine if licensing examination scores were associated with selected aspects of quality of care and resource use in initial primary care practice. DESIGN: Prospective cohort study of recently licensed family physicians, followed up for the first 18 months of practice. SETTING: The Quebec health care system. PARTICIPANTS: A total of 614 family physicians who passed the licensing examination between 1991 and 1993 and entered fee-for-service practice in Quebec. MAIN OUTCOME MEASURES: All patients seen by physicians were identified by the universal health insurance board and all health services provided to these patients were retrieved for the 18 months prior to (baseline) and after (follow-up) the physicians' entry into practice. Medical service and prescription claims files were used to measure rates of resource use (specialty consultation, symptom-relief prescribing compared with disease-specific prescribing) and quality of care (inappropriate prescribing, mammography screening). Baseline data were used to adjust for differences in practice population. RESULTS: Study physicians saw a total of 1116389 patients, of whom 113535 (10.2%) were elderly and 83391 (7.5%) were women aged 50 to 69 years. Physicians with higher licensing examination scores referred more of their patients for consultation (3.8/1000 patients per SD increase in score; 95% confidence interval [CI], 1.2-7.0; P = .005), prescribed to elderly patients fewer inappropriate medications (-2.7/1000 patients per SD increase in score; 95% CI, -4.8 to -0.7; P=.009) and more disease-specific medications relative to symptom-relief medications (3.9/1000 patients per SD increase in score; 95% CI, 0.3 to 7.4; P= .03), and referred more women aged 50 to 69 years (6.6/1000 patients per SD increase in score; 95% CI, 1.2-11.9; P = .02) for mammography screening. If patients of physicians with the lowest scores had experienced the same rates of consultation, prescribing, and screening as patients of physicians with the highest scores, an additional 3027 patients would have been referred, 179 fewer elderly patients would have been prescribed symptom-relief medication, 912 more elderly patients would have been prescribed disease-specific medication, 189 fewer patients would have received inappropriate medication, and 121 more women would have received mammography screening. CONCLUSIONS: Licensing examination scores are significant predictors of consultation, prescribing, and mammography screening rates in initial primary care practice.
Adult↗
Does hepatitis C virus co-infection accelerate clinical and immunological evolution of HIV-infected patients?
OBJECTIVE: To study the influence of hepatitis C virus (HCV) co-infection on clinical and immunological evolution of HIV-infected patients. DESIGN: A longitudinal study of HIV-infected individuals with or without HCV infection, identified at the Infectious Diseases Department of Dijon University Hospital and enrolled in a historical cohort, was performed. METHODS: One hundred and nineteen HIV-infected people co-infected with HCV and 119 matched individuals infected with HIV alone were included in the cohort (median participation time 3 years; range, 2 months to 11.5 years). Clinical progression was defined as one or more of the following: a 30% decrease in the Karnofsky index; a 20% loss of body weight; an AIDS-defining illness (for non-AIDS patients); death (except by accident, suicide or overdose). Immunological progression was defined as a 50% decrease in the initial CD4 T-cell count (for patients with an initial count > 100 x 10(6) cells/l). Effects of HCV co-infection were evaluated using Kaplan-Meier survival analysis and significance was tested using univariate (log-rank and Peto's tests) and multivariate methods (Cox's model). RESULTS: In univariate analysis, immunological progression was not statistically different between the HCV-positive group and the HCV-negative group, whereas clinical progression was significantly faster in HCV-positive patients (P < 0.005, log-rank test). In a multivariate Cox model, clinical progression remained significantly associated with infection by HCV [hazard ratio (HR), 1.64; 95% confidence interval (CI), 1.06-2.55; P < 0.05]. Stratified multivariable analysis retained HCV as a significant prognostic factor of clinical progression (HR, 10.9; 95% CI, 1.09-109.3; P < 0.05) and immunological progression (HR, 2.31; 95% CI, 1.16-4.62; P < 0.02) for patients with an initial CD4 count above 600 x 10(6) cells/l. CONCLUSIONS: Clinical progression is more rapid in HIV-HCV co-infected patients than in HIV-seropositive patients are not infected by HCV. The prognostic value of HCV infection for both clinical and immunological progression is significant at early stages of HIV infection. These findings may argue for active management of hepatitis C infection in co-infected individuals, especially for asymptomatic patients whose CD4 count is above 600 x 10(6) cells/l, to predict and prevent accelerated progression of HCV and HIV diseases.
Adult↗
Effect of splenectomy on slowing human immunodeficiency virus disease progression.
BACKGROUND: Lymphoreticular tissue is the most important site for human immunodeficiency virus (HIV) replication in HIV-infected individuals. OBJECTIVE: To compare the long-term effect of splenectomy on survival and time to development of acquired immunodeficiency syndrome in subjects who had undergone splenectomy with subjects who had not undergone splenectomy. DESIGN: A cohort study with a follow-up of up to 13.4 years. SETTING: Subjects were recruited from a hospital outpatient clinic population and a multicenter study of patients with hemophilia. PARTICIPANTS: Forty-five HIV-infected individuals were observed prospectively for up to 13.4 years (17 had undergone splenectomy and 28 had not undergone splenectomy). Five subjects underwent splenectomy before acquiring HIV infection and 12 underwent splenectomy during the asymptomatic phase of HIV infection. The group who did not undergo splenectomy consisted of HIV-infected individuals who were asymptomatic at study enrollment. MAIN OUTCOME MEASURES: A Cox proportional hazards model was used to test the effects of splenectomy on survival and time to development of acquired immunodeficiency syndrome when adjusting for potential confounders (age, initial CD4+ cell count, and treatment with antiretroviral drugs). Splenectomy was treated as a time-dependent covariate to account for the variation in its timing. RESULTS: During the average follow-up of 8.6 years, 9 (53%) of the 17 subjects who underwent splenectomy and 23 (82%) of the 28 subjects who did not undergo splenectomy died; acquired immunodeficiency syndrome developed in 6 (35%) of the subjects who underwent splenectomy and 23 (82%) of the subjects who did not undergo splenectomy. Splenectomy was associated with a significant reduction of risk of developing acquired immunodeficiency syndrome (adjusted relative risk [RR] <0.4, P<.05), whereas the effect on risk of mortality approached, although it did not reach, significance (adjusted RR approximately 0.5, P approximately .10). CONCLUSION: The absence of a spleen during the asymptomatic phase of HIV infection seems to have a beneficial effect on HIV disease progression.
Acquired Immunodeficiency Syndrome↗
Normal distributions of thermal and vibration sensory thresholds.
The distributions of sensory thresholds were estimated in a healthy population while controlling for potential covariates. Using the method of levels and the two-alternative forced choice, thermal and vibration thresholds respectively were measured in the hand and foot of 148 subjects. Age was uniformly distributed between 20 and 86 years. Independent effects of age, gender, height, and skin temperature were estimated using multiple linear regression. Parametric and nonparametric methods were used to estimate the distributions of interest. Significant age-related increases were observed for all vibration thresholds (P < 0.0001), and for thermal thresholds in the foot (P < 0.0002). Percentiles were estimated for thermal thresholds in the hand and age-adjusted continuous distributions were calculated for all other thresholds. Height was positively associated with vibration thresholds in the foot (P < 0.003), and appropriate corrections were made. Our results provide reference values for thermal and vibration sensory thresholds in a healthy population, allowing for the accurate diagnosis of disordered sensory function.
Adult↗
Development of a model for training and evaluation of laparoscopic skills.
BACKGROUND: Interest in the training and evaluation of laparoscopic skills is extending beyond the realm of the operating room to the use of laparoscopic simulators. The purpose of this study was to develop a series of structured tasks to objectively measure laparoscopic skills. This model was then used to test for the effects of level of training and practice on performance. METHODS: Forty-two subjects (6 each of surgical residents PGY1 to PGY5, 6 surgeons who practice laparoscopy and 6 who do not) were evaluated. Each subject viewed a 20-minute introductory video, then was tested performing 7 laparoscopic tasks (peg transfers, pattern cutting, clip and divide, endolooping, mesh placement and fixation, suturing with intracorporeal or extracorporeal knots). Performance was measured using a scoring system rewarding precision and speed. Each candidate repeated all 7 tasks and was rescored. Data were analyzed by linear regression to assess the relationship of performance with level of residency training for each task, and by ANOVA with repeated measures to test for effects of level of training, of repetition, and of the interaction between level of training and repetition on overall performance. Student's t test was used to evaluate differences between laparoscopic and nonlaparoscopic surgeons and between each of these groups and the PGY 5 level of surgical residents. RESULTS: Significant predictors of overall performance were (a) level of training (P = 0.002), (b) repetition (P < 0.0001), and (c) interaction between level of training and practice (P = 0.001). There was also a significant interaction between level of training and the specific task on performance scores (P = 0.006). When each task was evaluated individually for the 30 residents, 4 of the 7 tasks (tasks 1, 2, 6, 7) showed significant correlation between PGY level and score. A significant difference in performance scores between laparoscopic and nonlaparoscopic surgeons was seen for tasks 1, 2, and 6. CONCLUSIONS: A model was developed to evaluate laparoscopic skills. Construct validity was demonstrated by measuring significant improvement in performance with increasing residency training, and with practice. Further validation will require correlation of performance in the model with skill in vivo.
Education, Medical, Continuing↗
Prognostic factors for mortality in nasopharyngeal cancer: accounting for time-dependence of relative risks.
BACKGROUND: Few studies have assessed the role of prognostic factors for mortality from nasopharyngeal cancer and even fewer used multivariable methods. Most of these studies relied on the Cox model without testing the proportional hazards assumption. METHODS: A cohort of 76 cases of nasopharyngeal cancer recorded in the Rhône, France, between 1980 and 1985, was followed until 1995. Proportional hazards assumption was tested for each putative prognostic factor. Two multivariable models were built using forward selection of prognostic factors: the Cox model and a flexible model in which variables not meeting the proportional hazards assumption were represented by a time-varying hazard ratio. RESULTS: Only Epstein Barr Virus Nuclear Antigen (EBNA) serology, a marker of infection by the Epstein-Barr virus, and tumoral extent were selected in the analysis based on the Cox model. In contrast, four prognostic factors were significant at alpha = 0.05 level in the flexible model: initial EBNA serology, tumoral histology, age and tumoral extent, the last two not verifying the proportional hazards assumption. The relative risk of age increases with duration of follow-up whereas the effect of tumoral extent changes in a non-monotonic pattern. CONCLUSION: We showed the importance of taking into account the non-proportionality of hazards which can influence results and yield new insights about the role of prognostic factors in nasopharyngeal cancer. Because of the small size of our cohort, our results have to be confirmed in an independent study.
Adult↗
Impact of disease activity and cumulative damage on the health of lupus patients.
To test if lupus activity and damage predict physical function and general health in lupus was the objective of this study. Ninety-six patients with lupus were seen at baseline and monthly for 4 months. Sociodemographic characteristics and lupus damage (SLICC/ACR DI), were collected at baseline while lupus activity (SLAM-R, SLEDAI), health status measures (HAQ, SF-36) and immunological tests were collected at each visit. Associations of lupus activity and damage with general health and physical function were evaluated. Baseline health status measures were greatly impaired and comparable to those of severe medical illnesses. In cross-sectional analyses, baseline activity score measured by SLAM-R, but not by SLEDAI, correlated with most subscales of SF-36. Baseline damage score SLICC/ACR DI correlated only with the HAQ and the physical function subscale of SF-36. Differences in both activity measures (SLAM-R and SLEDAI) over time correlated with change in health status measures while baseline cumulative damage (SLICC/ACR DI) correlated with the average level of physical function only. Lupus activity measures, SLAM-R and SLEDAI, although differing cross-sectionally, both reflected patients' health status performance over time and lupus damage measure, SLICC/ACR DI, performed well in assessing physical function. Lupus patients scores for health are poor and comparable to those found in severe medical illnesses.
Activities of Daily Living↗
The relationship between disease activity and expert physician's decision to start major treatment in active systemic lupus erythematosus: a decision aid for development of entry criteria for clinical trials.
OBJECTIVE: To explore the relationship between patients' systemic lupus erythematosus (SLE) activity and physicians' decision to treat with steroids or alternative medication. METHODS: Baseline information and clinical status was extracted from case histories of 30 patients with lupus and represented in clinical vignettes. These vignettes were then mailed to 60 physicians (rheumatologists and immunologists with experience in the treatment of lupus), asking them in each case whether they would initiate treatment or not. The relationship between the 38 complete responses and the SLE Activity Measure (SLAM-R) and SLE Disease Activity Index (SLEDAI) lupus activity scores was analyzed using a general additive model. RESULTS: SLE disease activity measured by SLAM-R or SLEDAI is a significant predictor (p < 0.0001) of physicians' decision to initiate treatment for patients with lupus. Variation between physicians was observed but was mostly due to a few outliers. Some other variations remained unexplained by patients' SLE disease activity, damage, or by specific organ involvement. CONCLUSION: We present reference tables and curves for research that may be used as a basis to derive standardized quantitative criteria for entry in clinical trials. More research is needed on how these tools can be used by clinicians to guide them in their decision to treat or not.
Allergy and Immunology↗
Use of standardized patients to assess between-physician variations in resource utilization.
CONTEXT: As medical costs are increasingly being scrutinized, there is heightened interest in defining variations in physician behavior in clinical settings. OBJECTIVE: To evaluate if standardized patient (SP) technology is a reliable and feasible method of studying interphysician variations in test ordering, referral requests, prescribing behavior, and visit costs. DESIGN: The study was conducted with blinded SP visits to family medicine and internal medicine residents, university-affiliated family physicians, and community-based family physicians. Resource utilization and visit costs were assessed using test requisitions, consult requests, and prescriptions that were collected by the SPs. SETTING: Physicians' offices in ambulatory care, hospital-based clinics and in the community. PARTICIPANTS: Four persons (aged 57-77 years) trained to simulate having osteoarthritis of the hip. In one simulation, the patient had gastropathy due to nonsteroidal anti-inflammatory drug use, and in the other, the patient sought therapy for hip discomfort. MAIN OUTCOME MEASURES: Reliability of cost estimates of physician services, tests, consultations, prescriptions, and total visits and test-ordering behavior for nonsteroidal anti-inflammatory gastropathy. RESULTS: Overall, 112 (63%) of the physicians who were sent invitations to the study agreed to participate. Of 312 total SP visits conducted over a 1-year period, unblinding due to SP detection occurred on 36 occasions (11.5%). Reliable cost estimates of physician services, tests, and consultations, and moderately reliable estimates of total visit costs, were obtained with 4 visits per practicing physician and with 2 visits per resident. There were extreme variations in total visit costs generated by the study physicians. A small number of physicians had a major impact on this variability. CONCLUSION: Standardized patient technology provides a reliable, feasible method to assess variations in resource utilization between physicians.
Diagnosis-Related Groups↗
Predictive power of duplex ultrasonography in asymptomatic carotid disease.
BACKGROUND: Duplex ultrasonography is considered a valid measure of stenosis of the carotid arteries, but the prognostic value of repeated ultrasonographic examinations is unknown. OBJECTIVE: To determine the ability of serial ultrasonographic measurements to predict cerebrovascular events in patients with asymptomatic carotid disease. DESIGN: Secondary analysis of data from a natural history study of asymptomatic carotid disease. PATIENTS: Asymptomatic patients with cervical bruits. MEASUREMENTS: Duplex ultrasonography of the carotid arteries was done at study enrollment and biannually thereafter. Multivariable Cox proportional hazards models with fixed and time-dependent covariates were used for analysis. RESULTS: 61 transient ischemic attacks (TIAs) and 38 strokes occurred in 715 participants over a mean follow-up period of 3.2 years; 4 strokes were disabling, and no deaths from stroke occurred. Sixty percent of strokes occurred in persons who did not have severe stenosis. One fifth of participants had stenosis progression. Baseline carotid stenosis was a significant predictor of the outcome "TIA or stroke" (relative risk, 1.5 [95% CI, 1.2 to 1.7]) and retained its predictive ability for more than 3 years. Progression of stenosis to 80% or more significantly increased the risk for cerebrovascular events and death. The sensitivity and positive predictive value of progression as an independent predictor of TIA or stroke were low. CONCLUSION: Severe carotid stenosis is associated with a higher risk for cerebrovascular events, but the power of repeated ultrasonography to predict ischemic events is limited by low incidence rates and low rates of progression. The evidence does not support the routine use of serial ultrasonography to determine the risk for stroke in unselected patients with asymptomatic carotid disease.
Adult↗
Flexible modeling of the effects of serum cholesterol on coronary heart disease mortality.
Current understanding of the impact of lipids and other risk factors on coronary heart disease is largely based on the results of parametric multiple regression analyses of large prospective studies. To assess the potential impact of the a priori assumption of linearity of continuous risk factors on the results of parametric analyses, the authors completed a secondary analysis of the Lipid Research Clinics Prevalence and Follow-up Studies (1972-1987) data using an assumption-free nonparametric modeling approach. The effects of total serum cholesterol and the ratio of total serum cholesterol to high density lipoprotein cholesterol, adjusted for common risk factors, were estimated using a smoothing spline method available in the generalized additive model extension of the multiple logistic regression. The data set included 2,512 men in the random sample of the Lipid Research Clinics study who did not take lipid-lowering medications. During the median follow-up of 12.6 years, 94 coronary heart disease deaths occurred. The generalized additive model fits the effects of total serum cholesterol (p < 0.01) and the ratio of total serum cholesterol to high density lipoprotein cholesterol (p < 0.02) significantly better than the parametric logistic regression. Validation studies confirmed that, among new observations arising from the same population, generalized additive model estimates predicted outcomes better than the parametric estimates. Nonlinear effects of both lipid measures were robust and may be clinically important. The authors conclude that the linearity assumption inherent in parametric models may result in biased estimates of the effects of total serum cholesterol on coronary heart disease mortality and recommend that their findings be verified in a nonparametric analysis of data from another large prospective study.
Cholesterol↗
Outcome of asymptomatic patients with carotid disease. Asymptomatic Cervical Bruit Study Group.
Asymptomatic cervical atherosclerosis carries a variable risk of vascular events. We sought to identify patients with asymptomatic cervical bruits who may be at increased risk of developing ischemic events. We conducted a prospective multicenter cohort study of neurologically asymptomatic patients presenting a cervical bruit. Patients had biannual neurologic and carotid duplex evaluation. Association between ultrasonographic findings and vascular events, adjusting for common risk factors, was evaluated. Seven hundred fifteen patients were followed on average for 3.6 years. Mean age was 65 years. At initial visit, 357 subjects had a > or = 50% stenosis. Overall, 237 events occurred in 177 patients. Annual rate of all primary vascular events in patients with > or = 50% stenosis was 11.0% versus 4.2% in those with < 50% stenosis (p < 0.001). Annual rate of stroke and vascular death was 5.5% in the > or = 50% group compared with 1.9% in the < 50% group (p < 0.001). Yearly rate of unheralded ischemic stroke was 4.2% in subjects with > or = 80% stenosis and 1.4% in those with stenosis < 80% (p < 0.001). A stroke or TIA was ipsilateral to a > or = 80% stenosis in 66% of patients. Progression of carotid stenosis particularly to more than 80% was associated both with a higher rate of ipsilateral neurologic events and overall combined vascular events. Our data suggest that severity of carotid stenosis is the main risk factor predicting occurrence of neurologic and other vascular events. Yearly rate of ipsilateral stroke with > or = 50% carotid stenosis is low (1.4%) and most are nondisabling. Progression to > or = 80% or occlusion is associated with worse outcome.
Aged↗
Factors associated with growth of extremely premature infants during initial hospitalization.
OBJECTIVE: To quantify the factors associated with growth of very small premature infants during initial hospitalization. POPULATION: Study patients were 109 infants who were appropriate for gestational age, weighed <1000 g at birth, and were fed intravenous hyperalimentation then calcium-supplemented 81-kcal preterm formula according to a protocol. ANALYSIS: Multiple regression analysis was performed for periods of 0 to 56, 0 to 14, and 15 to 56 days of age. Growth was determined as change in weight during the period. Variables assessed in the initial model were caloric intake, protein intake, respiratory support duration, patent ductus arteriosus, dexamethasone use, infection, birth weight ratio (weight divided by expected intrauterine weight for gestation), gestational age, sex, calendar time from study start, maternal betamethasone administration, and necrotizing enterocolitis. For the 0 to 14-day period, maximum oxygen requirement for respiratory distress syndrome replaced respiratory support duration, and 5-minute Apgar score was added, whereas dexamethasone and necrotizing enterocolitis were deleted. RESULTS: Mean change in weight was 785 g for 0 to 56 days, -16 g for 0 to 14 days, and 770 g for 15 to 56 days. Mean weight was 94% (13 SD) of mean intrauterine at birth, 73% (10 SD) at 14 days, and 73% (12 SD) at 56 days. Regression models explained 85%, 43%, and 80%, respectively, of variation in growth. Of the initial variables assessed, the following were the independent prognostic determinants of growth. There was a positive association with caloric intake at 0 to 56 days and 15 to 56 days, and with protein intake at 0 to 14 days. Negative associations were found for birth weight ratio and gestational age at 0 to 56 and 0 to 14 days. Respiratory support duration was negatively associated at 15 to 56 days, and dexamethasone was negatively associated at 0 to 56 and 15 to 56 days. Formulas to predict growth were established from the final regression models. CONCLUSION: The growth failure in appropriate-for-gestational-age, <1000-g birth weight infants can be related in part to dexamethasone use and respiratory support duration. Increasing caloric intake and early protein intake improves growth. However, for the majority of these patients, early losses are not corrected completely by 56 days using currently recommended intakes.
Dexamethasone↗
Do too many cooks spoil the broth? Multiple physician involvement in medical management of elderly patients and potentially inappropriate drug combinations.
OBJECTIVES: To determine (a) whether the risk of a potentially inappropriate drug combination (PIDC) increases with the number of physicians involved in the medical management of an elderly patient and (b) whether the risk of a PIDC is reduced if a patient has a single primary care physician or a single dispensing pharmacy, or both. DESIGN: Cross-sectional retrospective provincial database study. PARTICIPANTS: A regionally stratified random sample of 51,587 elderly medicare registrants in Quebec who (a) visited at least one physician in 1990, (b) were not living in a health care institution for the entire year and (c) had been dispensed at least one prescription for a cardiovascular drug, a psychotropic drug or a nonsteroidal anti-inflammatory drug (NSAID). OUTCOME MEASURES: Information on all physician visits and drugs dispensed during 1990. Physician claims were used to identify the number of physicians involved in a patient's management and whether the patient had one primary care physician. Prescription claims were used to identify the number of PIDCs, prescribing physicians and dispensing pharmacies. RESULTS: The prevalence of PIDCs ranged from 4.0% (among those in the NSAID group) to 20.3% (among those in the psychotropic drug group). Of the PIDCs identified, 17.6% to 25.8% resulted from contemporaneous prescribing by different physicians. The number of prescribing physicians was the most important risk factor for a PIDC in all drug groups (odds ratio [OR] 1.44 to 1.71). The presence of a single primary care physician lowered the risk for cardiovascular and psychotropic PIDCs (OR 0.70 and 0.79 respectively) but not for NSAID PIDCs (OR 0.94). The use of a single dispensing pharmacy lowered the risk of a PIDC in all drug groups (OR 0.68 to 0.79). CONCLUSION: The greater the number of physicians prescribing medications for an elderly patient, the greater is the risk that the patient will receive a PIDC. A single primary care physician and a single dispensing pharmacy may be "protective" factors in preventing PIDCs.
Aged↗
Laboratory tests as predictors of disease exacerbations in systemic lupus erythematosus. Why some tests fail.
OBJECTIVE: To evaluate whether changes in laboratory test values are either simultaneous with or precede disease exacerbations in patients with systemic lupus erythematosus (SLE). METHODS: At 9, 6, and 3 months preceding a flare in disease activity (defined as a rise of > or = 6 points in the modified SLE Disease Activity Index), laboratory tests were performed to measure patients' hematocrit levels, white blood cell, lymphocyte, and platelet counts, erythrocyte sedimentation rate, C1q binding, DNA binding, and levels of C3 and C4. Flares were classified as either present or absent, and were divided into renal, vasculitic, central nervous system, skin, serosal, and musculoskeletal subgroups. The predictive patterns were 1) the simultaneous change in the test value from the mean of 9, 6, and 3 months preceding a flare to the time of the flare; 2) the gradual change, following a linear time trend, in test results for the same time points; and 3) the change from the mean of 9 and 6 months to 3 months preceding a flare, as a measure of predictive ability. These analyses used repeated-measures analysis of variance models. Multiple linear regression was used to study the cross-sectional association of average-over-time differences in test results with patients' flare subgroup. RESULTS: Among 202 patients with SLE (median followup 86.5 months), 83 flares occurred in 53 patients. Of 189 statistical contrasts performed, only 14 were significant (versus 10 expected), and the differences were of minor importance. Nonetheless, evaluation of all test results over each patient's observed disease course revealed significant differences between selected test values in association with specific types of flare. CONCLUSION: Fluctuations in laboratory test values are poor predictors of disease exacerbations in SLE. Cross-sectional evaluation of some test results revealed differences at the time of flare for those patients who were destined to have different types of flares, because these values differed over the entire study period. This pattern explains the frequent cross-sectional association of disease activity with laboratory test results, and the inconsistent association of flares with recent changes in test values.
Adolescent↗
The Quebec Back Pain Disability Scale: conceptualization and development.
The Quebec Back Pain Disability Scale is a new measure of functional disability for patients with back pain. Functional disability was operationalized in terms of perceived difficulty associated with simple physical activities. The content of the scale was developed in several stages, including a literature review, two studies seeking the opinions of patients and experts, pilot testing, and a large, longitudinal study of back pain patients. Forty-eight disability items were extensively studied using standard methods such as test-retest reliability, item-total correlations, and factor analysis, as well as modern techniques based on item response theory. Items that were highly effective in discriminating between different levels of disability were selected for the final, reduced scale. The scale has 20 items, representing six empirically derived categories of activities affected by back pain. Measurement properties of this instrument have been previously discussed.
Activities of Daily Living↗