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Biomedical subjects

D A Bloch

Publications and source records attributed to D A Bloch.

At least 19 recordsLinked to original sources
PubMed1992

Physical activity and fractures over the age of fifty years.

Our aim has been to determine the relationship between long term physical activity (running) and the number and type of fractures occurring in 906 subjects. Analysis focused on the fractures which occurred during the last 10 years of observation in 722 subjects over the age of 55 years (456 runners and 266 nonrunners). Male and female runners had more fractures than nonrunners, mainly in the lower extremity. Men with a high body mass had fewer total fractures and fewer arm fractures than those with a lower body mass. Men and women with a high calcium intake had fewer fractures from falls than those with a low calcium intake. Fewer fractures from falls occurred in women the longer they had been taking hormones.

Aged↗
PubMed1992

Osteophytosis of the knee: association with changes in weight-bearing exercise.

Osteoarthritis has been held to result from wear and tear. We addressed this hypothesis by analysis of anteroposterior radiographs of the knees of 51 subjects with mean age of 60 years who regularly practiced weight-bearing exercise. Radiographs were assessed for longitudinal changes in spur formation over a two-year period. The results showed a negative association between changes in weight-bearing exercise and changes in the rate of spur development in both males and females. The findings suggest that increasing repetitive impulse loading in the form of regular painless weight-bearing activity does not promote osteophytosis (or perhaps degenerative disease) in knee joints.

Aged↗
PubMed1992

Identification of work disability in rheumatoid arthritis: physical, radiographic and laboratory variables do not add explanatory power to demographic and functional variables.

Work disability, a common problem in rheumatoid arthritis (RA), is known to be associated with demographic variables such as occupation, age, and formal education, as well as with disease duration. However, physical, radiographic and laboratory variables, which are included in the traditional "medical model" of work disability and collected routinely in the application process, have not been studied for their capacity to explain whether patients are working or receiving work disability payments. A cross-sectional database which included an extensively characterized group of patients with RA was examined to determine possible associations of demographic, functional, physical, radiographic and laboratory variables with work disability status. All these variables differed in patients who were receiving work disability payments and those who were working full time, but in multivariate analyses, work or disability status was best identified by demographic and functional variables. Physical, radiographic, and laboratory data did not add significantly to explanation of work disability status beyond the demographic and functional variables and disease duration, despite the fact that receipt of disability payments was used as the criterion for work disability status.

Activities of Daily Living↗
PubMed1992

Impact of running on lumbar bone density: a 5-year longitudinal study.

Our study was designed to examine associations of longterm physical impact (running) with changes in lumbar bone mineralization. Study subjects were a volunteer sample of 14 members of a running club now aged 55 to 77 years and 14 matched controls undergoing computerized scans of the first lumbar vertebra both at baseline and after 5 years. Separate analyses included data from 23 runners available over the entire 5-year period. A decrease in bone mineral density (BMD) over time was statistically significant in both runners and controls. Among runners bone loss was most pronounced in those decreasing their running habits substantially. At the 5-year mark, runners maintained greater BMD. A highly significant correlation was found between change in lumbar BMD and average time spent running (min/week) over the 5-year period. Furthermore, changes in BMD were positively correlated with changes in run min/week. We conclude that regular running appears to reduce age related bone loss both in women and men over 50 years of age. However, substantial decreases in physical weight bearing activity are associated with important bone loss in the lumbar spine.

Aged↗
PubMed1992

Hypersensitivity vasculitis and Henoch-Schönlein purpura: a comparison between the 2 disorders.

Leukocytoclastic vasculitis of small vessels and predominant involvement of the skin are common features of both hypersensitivity vasculitis (HV) and Henoch-Schönlein purpura. In a study comparing 93 patients with HV and 85 patients with Henoch-Schönlein purpura we found major differences with respect to frequencies and type of organ involvement (gastrointestinal tract, kidneys, skin and joints) which were present in both younger and older patients when analyzed separately. To investigate which clinical criteria best differentiate between these 2 vasculitides, 2 methodologies were employed. A rule requiring 3 or more criteria to be present from a list of 6 yielded 87.1% of correctly classified Henoch-Schönlein purpura cases; and 2 or fewer criteria from the same list of 6 correctly classified 74.2% of HV cases. A classification tree was associated with respective values of 83.5 and 84.9%. The results indicate that HV and Henoch-Schönlein purpura are similar but separable clinical syndromes.

Adolescent↗
PubMed1991

Predictors of survival in systemic sclerosis (scleroderma).

We conducted followup of 264 patients with definite systemic sclerosis (SSc) who were entered into the multicenter Scleroderma Criteria Cooperative Study (SCCS) during 1973-1977. At the end of the study (average 5.2 years of followup), 38% were known to be alive, 50% were dead (68% of these deaths definitely related to SSc), and 12% were lost to followup. Survival analyses of 484 demographic, clinical, and laboratory items recorded at entry into the SCCS (within 2 years of physician diagnosis of SSc) were performed. Survival declined linearly, and the cumulative survival rate was less than 80% at 2 years, 50% at 8.5 years, and 30% at 12 years after entry. Analysis using combinations of entry variables identifying organ system involvement confirmed that renal, cardiac, pulmonary, and gastrointestinal involvement in SSc predicted reduced survival; however, data on organ system involvement at study entry could not be used to consistently predict which organ system would ultimately be involved as the primary cause of death. By survival tree analysis, the individual entry variables best predicting reduced survival included older age (greater than 64 years), reduced renal function (blood urea nitrogen greater than 16 mg/dl), anemia (hemoglobin less than or equal to 11 gm/dl), reduced pulmonary diffusing capacity for carbon monoxide (less than or equal to 50% of predicted), reduced total serum protein level (less than or equal to 6 gm/dl), and reduced pulmonary reserve (forced vital capacity less than 80% with hemoglobin greater than 14 gm/dl or forced vital capacity less than 65% with hemoglobin less than or equal to 14 gm/dl). Cox proportional hazards model analysis confirmed these results. Different combinations of variables led to markedly different survival rates. The poorest prospects for survival were in patients with SSc who were less than or equal to 64 years old with a hemoglobin level less than or equal to 11 gm/dl, and in those greater than 64 years old with a blood urea nitrogen level greater than 16 mg/dl. These results may be useful in predicting individual patients at risk for shortened survival.

Age Factors↗
PubMed1991

The progression of erosion and joint space narrowing scores in rheumatoid arthritis during the first twenty-five years of disease.

Erosions and cartilage destruction are nearly universal features in peripheral joints that have been chronically affected by rheumatoid arthritis. Scoring methods to measure the extent of these abnormalities in hands and wrists have been developed and have been thoroughly tested in several studies to establish their reproducibility. In this study, we utilized one of these scoring methods to examine the progression of radiologic damage as related to duration of disease. Two hundred ninety-two patients from 3 different participating centers in the Arthritis, Rheumatism, and Aging Medical Information System were included. Six hundred fifty films of the hands and wrists, obtained from 210 patients, were scored for erosions and joint space narrowing. The average annual rate of progression of the total radiologic score, which sums erosion and joint space abnormalities and has a maximum possible score of 314, was approximately 4 units per year over the first 25 years after onset; this progression was more rapid in the earlier years of disease and slightly slower in the later years. Data were insufficient to accurately determine the progression rate in disease of more than 25 years duration.

Arthritis, Rheumatoid↗
PubMed1991

The relative toxicity of nonsteroidal antiinflammatory drugs.

Toxicity Index scores were computed from symptoms, laboratory abnormalities, and hospitalizations attributed to nonsteroidal antiinflammatory drug (NSAID) therapy in 2,747 patients with rheumatoid arthritis receiving 5,642 courses of 11 NSAIDs over 8,481 patient-years. Substantial differences in overall toxicity were found, the differences between drugs often being clinically significant (2-3 times as toxic) and highly statistically significant. The results strengthened after adjustment for differing patient characteristics, held generally across multiple ARAMIS (Arthritis, Rheumatism, and Aging Medical Information System) data bank centers, and persisted after use of different techniques for the weighting of side effects. The most toxic side effects were experienced by patients taking indomethacin (mean +/- SEM score 3.99 +/- 0.58), tolmetin sodium (3.96 +/- 0.74), and meclofenamate sodium (3.86 +/- 0.66). Least toxic were coated or buffered aspirin (1.19 +/- 0.10), salsalate (1.28 +/- 0.34), and ibuprofen (1.94 +/- 0.43). The most toxic drugs were generally taken in the lowest relative doses. There are statistical differences in overall toxicity between different NSAIDs as used in rheumatoid arthritis, and these differences are both clinically and statistically significant.

Adverse Drug Reaction Reporting Systems↗
PubMed1991

Nonsteroidal anti-inflammatory drug-associated gastropathy: incidence and risk factor models.

PURPOSE: The most prevalent serious drug toxicity in the United States is increasingly recognized as gastrointestinal (GI) pathology associated with the use of nonsteroidal anti-inflammatory drugs (NSAIDs). The incidence of serious GI events (hospitalization or death) associated with NSAID use was therefore prospectively analyzed in patients with rheumatoid arthritis (RA) and patients with osteoarthritis. PATIENTS, METHODS, AND RESULTS: The study consisted of 2,747 patients with RA and 1,091 patients with osteoarthritis. The yearly hospitalization incidence during NSAID treatment was 1.58% in RA patients and was similar in all five populations studied. The hazard ratio of patients taking NSAIDs to those not taking NSAIDs was 5.2. The incidence in osteoarthritis may be less. The risk of GI-related death in RA patients was 0.19% per year with NSAIDs. Multivariate analyses assessing risk factors for serious GI events were performed in the 1,694 (98 with an event) RA patients taking NSAIDs at the predictive visit. The main risk factors were higher age, use of prednisone, previous NSAID GI side effects, prior GI hospitalization, level of disability, and NSAID dose. A rule is presented that allows estimation of the risk for the individual patient with RA. CONCLUSION: Knowledge of the risk factors for NSAID-associated gastropathy and their inter-relationships provides a tool for identification of the patient at high risk and for initiation of appropriate therapeutic action.

Adult↗
PubMed1991

Assessing predictive accuracy: how to compare Brier scores.

Several investigators have used the Brier index to measure the predictive accuracy of a set of medical judgments; the Brier scores of different raters who have evaluated the same patients provides a measure of relative accuracy. However, such comparisons may be difficult to interpret because of the lack of a statistical test for differentiating between two Brier scores. To demonstrate a method for addressing this issue we analyzed the judgments of five medical students, each of whom independently evaluated the same 25 patients with recurrent chest pain. Using the method we determined that two of the students gave judgments that were incompatible with the actual observed outcomes (p less than 0.05); of the three remaining students we detected a significant difference between two (p less than 0.05). These results differed from receiver operating characteristic curve area analysis, another technique used to evaluate predictive accuracy. We suggest that the proposed method can provide a useful tool for investigators using the Brier index to compare how well clinicians express uncertainty using probability judgments.

Chest Pain↗
PubMed1991

Pneumocystis carinii pneumonia and respiratory failure in AIDS. Improved outcomes and increased use of intensive care units.

To determine whether the outcome of intensive care for patients with AIDS, Pneumocystis carinii pneumonia (PCP), and respiratory failure has changed, we studied patients admitted to the intensive care units an San Francisco General Hospital from 1981 to 1988. We compared the course of patients with PCP and respiratory failure admitted to the intensive care unit from 1986 to 1988 with a similar cohort hospitalized from 1981 to 1985. The hospital survival rate for the 35 patients in the 1986 to 1988 cohort was 40%, compared with 14% for the 42 patients in the 1981 to 1985 cohort (p less than 0.01). Age, episode of PCP, time since AIDS diagnosis, anti-PCP therapy, and important clinical variables were similar in both cohorts. Corticosteroids were used commonly in the recent era. Patients who received steroids had an in-hospital survival rate of 46%, compared with 22% for those who did not receive steroids (p = NS). In a stepwise logistic regression model, ICU care in the recent era and higher serum albumin at the time of ICU admission were the only variables significantly associated with survival. The hospital survival of patients with PCP and respiratory failure has improved. The improvement could not be explained by patient selection or by better anti-PCP therapy. The apparent beneficial effect of corticosteroids deserves further study. The improvement in ICU outcome was reflected in increased ICU utilization by patients with AIDS, PCP, and respiratory failure.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Effect of changes in weight-bearing exercise on lumbar bone mass after age fifty.

This two year longitudinal study of 40 healthy subjects over age fifty (27 exercisers, 13 non-exercisers) was designed to evaluate the impact of weight-bearing exercise on lumbar bone mineral density as assessed by quantitative computed tomography. In both males and females exercising at moderate levels, a high correlation was found between changes in exercise and changes in bone density (r = 0.78 and 0.91, respectively P less than 0.002). For extreme levels of exercise (greater than 300 min/week in females over age fifty, and greater than 200 min/week in males over age seventy) bone density was low, confirming earlier cross-sectional results. Subjects without change in their exercise levels and non-exercisers lost similar amounts of bone. Increasing body mass index was identified as a protective factor with regard to lumbar bone loss. We conclude that in exercisers continuation of weight-bearing exercise is mandatory to prevent excessive bone loss. Extreme levels of exercise may be detrimental to bone density in subjects over age fifty years.

Bone Density↗
PubMed1991

Toxicity profiles of disease modifying antirheumatic drugs in rheumatoid arthritis.

The toxicity profiles of 7 disease modifying antirheumatic drugs (DMARD) (hydroxychloroquine, intramuscular (im) gold, D-penicillamine, oral gold, methotrexate (MTX), azathioprine and cyclophosphamide) were evaluated in 2,479 patients with rheumatoid arthritis consecutively enrolled at 5 centers in the Arthritis, Rheumatism and Aging Medical Information System (ARAMIS) program. Incidence rates for side effects are reported as events/1000 patient-years. Our descriptive study revealed an individual profile of prevalent toxicities for each drug. Oral gold was characterized by substantial lower gastrointestinal (GI) toxicity (diarrhea 391 events/1000 patient-years, loose bowel movement 148, lower abdominal pain 76), MTX by hepatotoxicity (47) while D-penicillamine had the only clinically significant incidence of altered taste (40). MTX users reported the most mucosal ulcers (87), followed by oral gold (76), im gold (55) and D-penicillamine (38). Rash was frequently seen with gold compounds and D-penicillamine, while upper GI toxicity was common with immunosuppressive agents. Cyclophosphamide had 48% discontinuations within 6 months. MTX had the lowest discontinuation rate in the first 6 months, but then showed little difference from im gold. A preliminary similarity index was developed to compare the toxicity profiles of various DMARD. Close similarities were found between toxicity profiles of im gold and D-penicillamine, and between azathioprine and MTX. Oral gold had a unique toxicity pattern. Knowledge of these different toxicity patterns can enable more appropriate selection of agents for particular patients.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1991

Predictors of fractures in early rheumatoid arthritis.

Three hundred ninety-five patients with rheumatoid arthritis (mean age 49 years) were followed for an average of 6.7 years, and their baseline variables from the initial visit were examined for prediction of time to first fracture. Multivariate analyses identified use of corticosteroids in women and prior diagnosis of osteoporosis as important risk factors. Among patients taking 5 mg or more of prednisone, female sex strongly predicted fractures: the 5-year probability of having a fracture was 34%. Low risk groups were nonosteoporotic and consisted of men and patients taking less than 5 mg prednisone.

Adolescent↗
PubMed1990

The American College of Rheumatology 1990 criteria for the classification of vasculitis. Patients and methods.

The American College of Rheumatology Subcommittee on Classification of Vasculitis of the Diagnostic and Therapeutic Criteria Committee developed classification criteria for 7 forms of vasculitis: polyarteritis nodosa, Churg-Strauss syndrome, Wegener's granulomatosis, hypersensitivity vasculitis, Henoch-Schönlein purpura, giant cell (temporal) arteritis, and Takayasu arteritis. The data collection methods, quality control, and analytic procedures used to derive the classification rules are discussed herein.

Data Collection↗
PubMed1990

The American College of Rheumatology 1990 criteria for the classification of polyarteritis nodosa.

Criteria for the classification of polyarteritis nodosa were developed by comparing 118 patients who had this disease with 689 control patients who had other forms of vasculitis. For the traditional format classification, 10 criteria were selected: weight loss greater than or equal to 4 kg, livedo reticularis, testicular pain or tenderness, myalgias, mononeuropathy or polyneuropathy, diastolic blood pressure greater than 90 mm Hg, elevated blood urea nitrogen or serum creatinine levels, presence of hepatitis B reactants in serum, arteriographic abnormality, and presence of granulocyte or mixed leukocyte infiltrate in an arterial wall on biopsy. The presence of 3 or more of these 10 criteria was associated with a sensitivity of 82.2% and specificity of 86.6%. A classification tree was also constructed, with 6 criteria being selected. Three of these, angiographic abnormality, biopsy-proven granulocyte or mixed leukocyte infiltrate in arterial wall, and neuropathy, were criteria used in the traditional format. The other 3 criteria used in the tree format included the patient's sex, weight loss greater than 6.5 kg, and elevated serum aspartate aminotransferase or alanine aminotransferase levels above the range of normal. The classification tree yielded a sensitivity of 87.3% and a specificity of 89.3%.

Diagnosis, Differential↗