Where do we go from here? Opportunities for applying health status assessment measures in clinical settings.
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Biomedical subjects
Publications and source records attributed to H A Guess.
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The incidence of surgically treated benign prostatic hypertrophy and of prostate cancer was examined to December 1987 in 14,897 men (2,175 blacks and 12,722 whites) who received multiphasic health checkups during 1971-1972 while members of the Kaiser Permanente Medical Care Program (San Francisco-Oakland, California). Prostate cancer incidence was higher in blacks than in whites for all age groups (age-adjusted relative risk (RR) = 1.8, 95% confidence interval (CI) 1.4-2.3). The incidence of benign prostatic hypertrophy was somewhat higher in blacks than in whites until age 65 years, after which it was higher in whites. In contrast to the risk of prostate cancer, the age-adjusted risk of benign prostatic hypertrophy was the same for blacks as for whites (RR = 1.0, 95% Cl 0.8-1.2).
The relationship of vasectomy to prostate cancer was studied in 5,119 men men with a self-reported history of vasectomy, identified at multiphasic health checkups undergone during 1977-82 while members of the Northern California Kaiser Permanente Medical Care Program. Three unvasectomized comparison subjects were identified for each vasectomized man, matched for age, race, marital status, and date and location of the examination. Follow-up for incident prostate cancer was conducted for a mean length of 6.8 years. The relative risk of prostate cancer associated with vasectomy was 1.0 (95% confidence interval = 0.7 - 1.6); the relative risk was approximately one, regardless of length of interval (less than 10 years, 10-20 years, more than 20 years) between vasectomy and multiphasic health checkup or the age at vasectomy (less than 40 years vs more than 40 years). These data support earlier findings reported in this study group of the lack of an association of vasectomy with subsequent risk of prostate cancer.
The natural history of prostatism (clinically diagnosed benign prostatic hyperplasia) is examined based on symptom questionnaires and digital rectal examinations administered periodically to 1,057 men followed prospectively for up to thirty years in the Baltimore Longitudinal Study of Aging (BLSA). Benign prostatic hyperplasia (BPH) was clinically diagnosed in 527 men, 110 had a prostatectomy for BPH, and in 21 prostate cancer developed. Among men aged sixty or older with prostatic enlargement and obstructive symptoms, the twenty-year probability of surgery was 39 percent; for men aged fifty to fifty-nine years this probability was 24 percent; and for men aged forty to forty-nine years, the probability was 13 percent. The age-specific prevalence of clinically diagnosed BPH agreed closely at all ages with the age-specific autopsy prevalence of pathologically defined BPH from a published international compilation of 5 independent autopsy studies involving 1,075 prostates.
The relationship of age, medical history, personal habits, and urologic symptoms to the incidence of surgically treated benign prostatic hyperplasia (BPH) was studied in a cohort of 16,219 men, aged forty years and over, who received multiphasic health checkups (MHCs) during 1971 and 1972 in Oakland or San Francisco while members of the Northern California Kaiser Permanente Medical Care Program, a large prepaid health care program. Follow-up was carried out for surgically treated BPH from the date of the MHC to the date of the earliest of the following: surgery for BPH (n = 1,027); incidence of prostate cancer (n = 329), bladder cancer (n = 119), or both (n = 10); other prostate surgery (n = 5); death (n = 2,525); membership termination (n = 4,235); or December 31, 1987 (n = 7,969). The mean length of follow-up was twelve years. In multivariate analysis utilizing the Cox proportional hazards model, the following characteristics were positively associated (p less than 0.05) with risk of surgically treated BPH: age, low body mass index, nonsmoking (vs. current smoking), urine pH greater than 5, history of kidney x-ray and of tuberculosis, and each of five urologic symptoms (dysuria, loss of bladder control, trouble starting urination, nocturia, slow urine stream). The risk of BPH associated with obstructive urologic symptoms decreased markedly with age. Some of these findings are consistent with those from other studies (age, nonsmoking), while others (high urine pH, history of tuberculosis) are new and should be examined in other study populations.
In a pilot study of a urinary symptom and health-related quality-of-life questionnaire for benign prostatic hyperplasia (BPH), responses from 64 Mayo Clinic patients with cystoscopic evidence of obstructive BPH were compared with those of 14 men with no cystoscopic evidence of BPH and a community sample of 64 comparably aged men with no medical history of prostate enlargement. Questions which best discriminated between the groups were those dealing with urinary symptom frequency, bother due to urinary symptoms, and worry and concern about urinary problems. The results suggest that urinary-symptom-bother and worry due to urinary symptoms may be important additions to the more usual questions asked about urinary frequency in the identification of men with BPH. These findings are preliminary, however, and will be verified in an ongoing natural history study of BPH.
The incidence and outcome of surgery for benign prostatic hyperplasia (BPH) was studied in Rochester, Minnesota, during the period 1980-1987. Three hundred thirty Rochester men without a diagnosis of prostate or bladder cancer underwent prostatectomy for BPH for the first time. Mean and median ages were both seventy (range: 46-95). The incidence of initial prostatectomy for BPH among men forty-five years of age and older age-adjusted to the 1980 U.S. white male population was 642 cases per 100,000 persons per year (py). Among the 330 men undergoing initial prostatectomy for BPH, 14 (4.2%) had serious intraoperative complications, 32 (9.7%) were rehospitalized for urologic complications within thirty days of surgery, and 13 (3.9%) had other serious complications within thirty days after surgery, including 1 death (surgical mortality 0.3%). Forty-five patients (14%) required blood transfusions within thirty days of surgery. The likelihood of reoperation within six years of the initial surgery was 15.1 percent (95% CI 9.7, 20.6). Short- and long-term postoperative mortality was not statistically significantly different than expected based on age- and sex-specific mortality statistics for Rochester, Minnesota.
A large double-blind, randomized, placebo-controlled trial of live attenuated Oka/Merck varicella vaccine was conducted among healthy children, 1-14 years of age. During the first varicella season, the efficacy of the vaccine among susceptible children was 100%1. During the second varicella season, 22 children were diagnosed with varicella; 21 cases in placebo recipients and one in a vaccine recipient. The overall efficacy of the vaccine through two varicella seasons was 98%. After the code for the study was broken, the original group of vaccine recipients continued to be followed for development of varicella. The estimated proportion of vaccine recipients who remained varicella-free at the end of 7 years was 95%. The 23 cases of varicella that occurred in vaccine recipients over the 7-year period were considerably milder than natural varicella. The average number of lesions was 53, 50% of the children had non-vesicular rashes, and 14% of the children had a temperature greater than or equal to 38.9 degrees C (102 degrees F), oral. The persistence of antibody in a subset of vaccine recipients followed for 6 years was 100%.
We present a concept of pharmacoepidemiology as a branch of clinical epidemiology having particular relevance to public health in developing countries. Planning to incorporate pharmacoepidemiology into the clinical epidemiology curriculum of the International Clinical Epidemiology Network (INCLEN) is discussed and an outline of training programs in pharmacoepidemiology at INCLEN universities is given.
Applications of pharmacoepidemiology to the pre-approval safety monitoring of investigational drugs are examined and compared with the post-approval applications. Pre-approval epidemiologic assessments of drug safety can complement clinical assessments of rare, serious adverse events occurring in open label uncontrolled clinical trials. Applications include retrospective identification of patient risk factors for adverse drug events and incidence comparisons based on historical controls. While similar in concept to applications of pharmacoepidemiology in the analyses of uncontrolled open label post-marketing surveillance studies, answers are often needed in days rather than weeks and the emphasis is on whether human studies can continue. Advance planning of historical data sources is essential as is an effective clinical trial data management system. Implications for methodologic research and for drug development are discussed.
To evaluate the incidence and outcome of initial surgery for benign prostatic hyperplasia (BPH) and to clarify the natural occurrence and progression of such urologic diseases, two studies have been conducted in a free-living population in Rochester, MN. The first followed 330 men who had not been diagnosed with prostate or bladder cancer at the time of prostatectomy. All surgery subjects were area residents and between 46 and 95 years of age (mean age 70 years). Among the operated subjects, 14 (4.2%) had serious intraoperative complications, 32 (9.7%) were rehospitalized for urologic complications within 30 days after surgery, and 13 (3.9%) experienced other serious complications in that same time period. Blood transfusions within 30 days of surgery were necessary in 45 patients (14%). The risk of reoperation within 6 years of the initial surgery was calculated at 15.1% (95% CI: 9.7, 20.6). On the basis of age- and sex-specific mortality statistics for Rochester, short- and long-term postoperative mortality was not statistically significantly different from that expected. Results of the second study are not yet available. This population-based evaluation of the natural history of urologic disease is expected to clarify the relative utility of various treatment options and provide a useful perspective on the management of BPH.
Symptom questionnaires and physical examinations administered periodically to 1,057 men followed prospectively for up to 30 years in the Baltimore Longitudinal Study of Aging (BLSA) were analyzed to determine which symptoms of prostatism were predictive of subsequent prostatectomy for benign prostatic hyperplasia (BPH). Change in the size and force of the urinary stream (P = 0.0001) and a sensation of incomplete emptying (P = 0.0005) were the only symptoms positively predictive in a multivariate analysis. Prostate enlargement by rectal palpation was an independent risk factor for prostatectomy (P less than 0.03) and was associated with hesitancy (P less than 0.02) and a sensation of incomplete emptying (P less than 0.02). Of the men with all three risk factors, 37% (41/112) eventually had a prostatectomy, in contrast to 8% of the remaining 945 men. This is the first study to document the extent to which urologic symptoms and a digital rectal examination predict subsequent prostatectomy for BPH.
The age-specific cumulative prevalence of clinically diagnosed prostatism among 1,057 generally healthy men followed for up to 30 years in the Baltimore Longitudinal Study of Aging was compared with the age-specific autopsy prevalence of pathologically defined benign prostatic hyperplasia (BPH) from a published compilation of five independent autopsy studies involving 1,075 prostates. Clinical prevalences based on medical histories and digital rectal examinations showed excellent agreement with autopsy prevalences at all ages. Despite the well-known lack of correspondence between prostatism and objective urologic evidence of BPH in individual patients, these results suggest that the proportion of the male population with clinically recognizable prostatism by a given age is about the same as the proportion with pathological evidence of BPH.
A rapidly converging algorithm is given to calculate exact confidence intervals about the adjusted relative risk in follow-up studies with stratified incidence-density data. The network approach that Mehta developed for tables with person-count numerators and denominators is adapted to tables with person-count numerators and person-time denominators. This algorithm updates an earlier program by Guess et al, yielding the same quantities but with running times that are between ten and a hundred times faster. Applications to Poisson regression are discussed.
The incidence of invasive Haemophilus influenzae infections was studied among all residents of Rochester, Minnesota, under 20 years of age during the period 1975-1983. The incidence in children under 5 years of age was 115 and 64 cases per 100,000 children per year for all invasive cases and for meningitis, respectively. These rates are among the highest reported for an essentially all-Caucasian population in the United States, while the ratio of meningitis to non-meningitis cases (1.1:1) is among the lowest. This suggests possible under-ascertainment of non-meningitis cases in previous US studies of Haemophilus influenzae infections.
Soon after the plasma-derived hepatitis B vaccine became available in the US, the Centers for Disease Control and the manufacturer received over 100 reports of vaccinated groups with unexpectedly low levels of vaccine-induced antibody. To confirm previous retrospective surveys relating these failures to buttock injection and to evaluate the effect of other host factors on vaccine-induced antibody responses, we conducted a clinical trial in healthy health-care workers. Participants were randomly assigned to one of three treatment groups: 1-Ar, 1-inch needle injection in the arm; 1-Bu, 1-inch needle injection in the buttock; 2-Bu, 2-inch needle injection in the buttock. All participants were administered vaccine according to the standard vaccine dosage schedule of 20 micrograms at 0, 1 and 6 months. Antibody response rates (antibody to hepatitis B surface antigen greater than or equal to 10 sample ratio units by radioimmunoassay) and geometric mean titres of antibody two months after the third vaccine dose were 93% and 1454 mIU ml-1 for group 1-Ar, 72% and 85 mIU ml-1 for group 1-Bu, and 83% and 387 mIU ml-1 for group 2-Bu. Seroconversion rates and titres of antibody in the three groups were significantly different from each other statistically. Increasing age, increasing total skinfold thickness and cigarette smoking were independently associated with lower antibody responses in persons receiving buttock injections but not in persons receiving arm injections.(ABSTRACT TRUNCATED AT 250 WORDS)
Oka strain varicella vaccine generally has been well tolerated by children with acute lymphocytic leukaemia (ALL) in remission and has induced protection against disease caused by wild-type varicella virus. At the end of 1985, four extensive vaccine-associated rashes were reported among children on maintenance chemotherapy. Steroid therapy in the week before vaccination or in the week following vaccination was significantly associated with rash in a retrospective analysis (odds ratio = 3.84, p = 0.0006). These findings were confirmed prospectively (OR = 2.38, p less than 0.05, one-sided) in a second smaller group of children with ALL on maintenance therapy who received varicella vaccination after the end of the data collection for the initial study but before the relationship between rash and steroids was discovered. As a result of these studies, investigators have been asked to withhold steroids for 1 week before vaccination and to delay resumption of steroid therapy for at least 2 weeks after vaccination. These results should serve as a caution that vaccination of these children should be undertaken only with full knowledge of their therapeutic regimen and a thorough clinical understanding of the competing risks of varicella, vaccination and modification of the child's chemotherapy.
In case-control studies of adverse drug effects there is rarely much evidence to support the assumption that the hazard function among users is constant during therapy. Nonetheless, this assumption is often implicitly made. We will use both clinical reasoning and a simple model to show how non-constancy of the hazard function affects odds ratio interpretation. When the hazard function is non-constant and there is more than one temporal pattern of drug usage, the odds ratio will estimate a weighted mean of incidence ratios with weights dependent on the corresponding fractions of person-time. If the duration-specific incidence ratios differ widely, the odds ratio will depend not only on the drug but also on its usage pattern in the study population. This may explain some of the large regional odds ratio variation for dipyrone-related agranulocytosis in the International Agranulocytosis and Aplastic Anemia Study (JAMA 1986; 256: 1749-1757.