Search PubMed⌕ Search

Biomedical subjects

H A Guess

Publications and source records attributed to H A Guess.

At least 73 records · Page 4Linked to original sources
PubMed1994

Correlation between urinary flow rate, voided volume, and patient age in a community-based population.

This investigation is unique in that is the first study to use a large number of randomly chosen men from the community to establish the relationship between: 1) urinary flow rate and voided volume, 2) urinary flow rate and patient age, 3) voided volume and patient age, and 4) the time to achieve peak urinary flow rate and patient age. The results clearly indicate that both the peak and mean urinary flow rate decreases with advancing age. The voided volume also diminishes with increasing age. The time required to achieve the peak urinary flow rate, however, appears to be independent of the patient's age. Irrespective of age, approximately 9 seconds are required to achieve the maximum urinary flow rate. Because the urinary flow rate is dependent upon both the quantity of urine voided and the patient's age, it is necessary to account for the influence of both parameters when establishing the "normal range" for peak urinary flow rate. To this end, nomograms estimating the peak urinary flow rate percentile as a function of voided volume and patient age have been generated and are included in this report. These nomograms, based on a large, randomly selected population, should make peak urinary flow rate a more reliable diagnostic modality for assessing bladder outlet obstruction. They also should be most useful to the practicing clinician when interpreting the results of a peak urinary flow rate determination for a patient presenting with symptoms of prostatism.

Adult↗
PubMed1993

Serum prostate-specific antigen in a community-based population of healthy men. Establishment of age-specific reference ranges.

OBJECTIVE: To define the characteristics of serum prostate-specific antigen (PSA) in a population of healthy men without clinically evident prostate cancer, but who are at risk for developing the malignancy. The influence of patient age and prostatic size on the serum PSA concentration was assessed in order to use PSA more appropriately to detect clinically significant prostate cancer at an early, potentially curable stage. DESIGN: Prospective, community-based study. PARTICIPANTS: Between December 1989 and March 1991, 2119 healthy men aged 40 to 79 years from Olmsted County, Minnesota, were entered into a prospective study to assess the natural history of benign prostatic hyperplasia. Of these, 537 (25%) were randomly chosen to participate in a detailed clinical examination that included a serum PSA determination (Tandem-R PSA assay), digital rectal examination, and transrectal ultrasonography. Four hundred seventy-one (88%) completed the prostatic evaluation and had no evidence of prostate cancer by any of these three diagnostic tests; these men formed the study population on which all analyses were performed. MAIN OUTCOME MEASURE: Serum PSA concentration, prostatic volume, and PSA density (serum PSA level/prostatic volume) as a function of patient age. RESULTS: The serum PSA concentration is correlated with patient age (r = .43; P < .0001) and prostatic volume (r = .55; P < .0001). Prostatic volume, in turn, is directly correlated with patient age (r = .43; P < .0001), whereas the PSA density value is only weakly correlated with patient age (r = .25; P < .001). For a healthy 60-year-old man with no evidence of prostate cancer, the serum PSA concentration increases by approximately 3.2% per year (0.04 ng/mL per year). The recommended reference range for serum PSA (95th percentile) for men aged 40 to 49 years is 0.0 to 2.5 ng/mL; for 50 to 59 years, 0.0 to 3.5 ng/mL; 60 to 69 years, 0.0 to 4.5 ng/mL; and 70 to 79 years, 0.0 to 6.5 ng/mL. CONCLUSIONS: The serum PSA concentration is directly correlated with patient age and prostatic volume, the latter of which also is directly related to age. Thus, rather than rely on a single reference range for men of all age groups, it is more appropriate to have age-specific reference ranges. These age-specific reference ranges have the potential to make serum PSA a more discriminating tumor marker for detecting clinically significant cancers in older men (increasing specificity) and to find more potentially curable cancers in younger men (increasing sensitivity).

Adult↗
PubMed1993

A population-based study of health care-seeking behavior for treatment of urinary symptoms. The Olmsted County Study of Urinary Symptoms and Health Status Among Men.

OBJECTIVE: To determine the extent to which severity of urinary symptoms predicts a man's decision to seek medical care for urinary symptoms. DESIGN: Cross-sectional, population-based survey; the baseline component of a prospective cohort study. SETTING: Olmsted County, Minnesota (1990 population, 105,720), including the city of Rochester (population, 69,995) and surrounding rural townships. SUBJECTS: A population-based sample of men aged 40 to 79 years randomly selected within age- and residence-specific strata. INTERVENTION: A previously validated questionnaire that elicited information about the frequency and bother of urinary symptoms, sociodemographic information, and information regarding use of physician services in the last year. MAIN OUTCOME MEASURE: An affirmative response to any of 12 questions asking the subject if he had seen a physician in the last year because of specific urinary symptoms. MAIN RESULT: Symptom severity, whether measured by American Urologic Association frequency or bother score or by interference with daily activities, was a significant predictor of health care-seeking behavior for urinary symptoms, but was neither as sensitive nor as specific as would be ideal. After adjusting for symptom severity and sociodemographic characteristics, men aged 70 to 79 years were 4.6 times as likely (95% confidence interval, 2.1 to 10.1) as men aged 40 to 49 years to have sought health care because of urinary symptoms in the last year. CONCLUSION: While symptom severity is an important determinant of health care-seeking behavior for men with urinary symptoms, some additional factor or factors associated with age remain that may drive men to seek care for urinary symptoms. These factors may prove important in understanding the small-area variations in treatment of benign prostatic hyperplasia that have been noted by others.

Adult↗
PubMed1993

The effect of finasteride on prostate-specific antigen in men with benign prostatic hyperplasia.

Finasteride is a specific 5-alpha-reductase inhibitor that has been shown to reduce prostate size and decrease serum levels of prostate specific antigen (PSA). Among men who received finasteride (5 mg/day) for 12 months in North American clinical trials and in whom prostate cancer was not diagnosed the median percentage change in PSA was -50% (5-95% range: -81% to +20%). At baseline 72% had PSA < or = 4.0 ng/ml and 93% had PSA < or = 10.0 ng/ml. After 12 months on finasteride, 75% had PSA < or = 2.0 ng/ml and 95% had PSA < or = 5.0 ng/ml. Thus, the proportion of BPH patients with PSA levels of 2.0 ng/ml and 5.0 ng/ml after 12 months of treatment was comparable to the proportion with pretreatment PSA levels of 4.0 ng/ml and 10.0 ng/ml. Among the 10 men in these trials subsequently diagnosed with prostate cancer while on long-term finasteride therapy (5 mg/day), the median percentage change in PSA was -26% (range: -48% to +12%). Limited experience with finasteride in men with prostate cancer suggests that the reduction in PSA of malignant origin appears to be no greater than the percentage reduction in PSA of benign origin. These effects on PSA have not been shown to confer any therapeutic benefit. Physicians using finasteride should be aware of its effect on PSA levels.

5-alpha Reductase Inhibitors↗
PubMed1993

Natural history of prostatism: factors associated with discordance between frequency and bother of urinary symptoms.

The objective of this study was to assess the association between frequency and bother of urinary symptoms in a population-based cohort of men and to identify psychosocial factors that are related to reporting heightened or subdued bother relative to symptom frequency. The survey was conducted among men aged forty to seventy-nine years in Olmsted County, Minnesota, the baseline component of a prospective cohort study. Men were queried about the frequency of urinary symptom occurrence and the perceived bother associated with the symptoms. A regression analysis of American Urologic Association (AUA) bother scores on AUA frequency scores demonstrated a tight correspondence (r2 = 0.71). Men with bother scores greater than predicted from their frequency scores were more likely to have sought health care for their urinary symptoms than men whose bother was close to predicted (14 versus 5 percent, respectively). These men with heightened bother were older, poorer, more anxious, and had lower general psychologic well-being scores than the men whose bother was similar to that expected from their reported frequency. Men whose bother was lower than would be expected were less likely to have sought health care for urinary symptoms in the past year (3%) but were of similar age and socioeconomic status as compared with men whose bother was close to expected. These men, however, were more depressed than men whose bother was commensurate with reported frequency. While the men who reported greater bother than expected from their symptom frequency were more likely to have sought medical care for urinary symptoms in the past year, it is not clear whether this greater health-care-seeking behavior is because bother captures an additional component of urologic disease or is a manifestation of psychosocial differences.

Adult↗
PubMed1993

Time-dependent variability in repeated measurements of cholesterol levels: clinical implications for risk misclassification and intervention monitoring.

Intraindividual variability (IIV) in total cholesterol levels based on measurements taken 1 week apart is compared with an estimate based on measurements taken 2 years apart. Single-subject 95% confidence intervals around the mean of two repeated measurements were Xi +/- 21 and +/- 28 mg/dl, respectively, and Xi +/- 30 and +/- 40 mg/dl for a single measurement. Comparing these results with published estimates over varying time intervals shows a trend of decreasing IIV with shorter intervals, suggesting that confidence interval widths based on short-term repeated measurements and those based on longer-term repeated measurements may differ more than previously assumed. The practical consequences are that: (1) the level of misclassification inherent in the National Cholesterol Education Program (NCEP) guidelines may be less than had been estimated; and (2) reliable cholesterol reductions resulting from dietary or other interventions may be somewhat easier to detect. These findings have implications for the cost-effectiveness of cholesterol screening strategies and interventions to reduce cholesterol.

Adult↗
PubMed1993

The prevalence of prostatism: a population-based survey of urinary symptoms.

To establish the age-specific prevalence of urinary symptoms among a community-based cohort of men, a randomly selected sample of men were screened and invited to participate in a longitudinal survey of urinary symptoms. The population of Olmsted County, Minnesota, as enumerated by the Rochester Epidemiology Project, formed the sampling base for this study. Men between 40 and 79 years old with no history of prostate or other urological surgery, and who also were free of conditions associated with neurogenic bladder were invited to participate. A previously validated questionnaire was completed by the subject. Urine flow measures, current medications and family histories of urinary disease were also obtained. Nonresponse corrected scores for a composite of obstructive symptoms showed moderate to severe symptomatology among 13% of the men 40 to 49 years old and 28% of those older than 70 years. Prostatism is a highly prevalent symptom complex among unselected men in the community. The specific urinary symptoms of nocturia, weak stream, restarting, urgency and sensation of incomplete emptying are strongly age-related and, therefore, may be predictive of a prostatic disease process.

Adult↗
PubMed1993

Natural history of prostatism: urinary flow rates in a community-based study.

Urinary flow rates were measured in a randomly selected community sample of more than 2,000 men 40 to 79 years old with no history of prostate surgery, prostate cancer or certain other diseases known to interfere with normal voiding. Peak urinary flow rates decreased from a median of 20.3 ml. per second in men 40 to 44 years old to 11.5 ml. per second for men 75 to 79 years old, while voided volumes decreased from a median of 355.5 to 222.5 ml. for the same age ranges. Peak flow rates of less than 10 ml. per second were found in 6% of the men aged 40 to 44 years, increasing to 35% among men aged 75 to 79 years. Urological standards for peak urinary flow rate should be based on community data, and should account for age and voided volume. Our study may serve as the starting point for the development of community-based flow rate normal ranges. Nomograms are given to permit estimating flow rate percentiles as a function of age and voided volume.

Adult↗
PubMed1993

Similar levels of urological symptoms have similar impact on Scottish and American men--although Scots report less symptoms.

Urinary symptoms and the extent to which they interfere with living activities were compared in 2 community-based investigations that enrolled men 40 to 79 years old who were randomly sampled from Olmsted County, Minnesota (2,119) and the Forth Valley of Scotland (1,385). Both investigations included symptom questions with wording that is nearly identical to that of the American Urological Association (AUA) symptom index. Following AUA scoring conventions we grouped scores into mild (AUA score 0 to 7), moderate (score 8 to 19) and severe (score 20+) categories. Minnesota men had symptoms that were more frequent, more bothersome and caused greater interference with living activities than did Scottish men of comparable age (p < 0.0002). However, within each symptom score category, the extent to which symptoms interfered with living activities was essentially the same in both populations. Although there appear to be important differences in urinary symptom prevalence between Scotland and Minnesota, the AUA symptom index provides a consistent measure of the extent to which urinary symptoms interfere with living activities in both populations. These findings support use of the AUA symptom index in the diagnostic evaluation of men with benign prostatic hyperplasia.

Adult↗
PubMed1993

Is vasectomy a risk factor for prostate cancer?

Recently, several case-control studies have suggested that vasectomy may predispose to prostate cancer. Other studies have found no increase in risk. All of these studies have a number of limitations. Taken together, these studies do not provide convincing evidence that vasectomy increases the risk of prostate cancer. However, in view of the high prevalence of prostate cancer and the growing worldwide importance of vasectomy as a form of contraception, further epidemiological research is warranted. After briefly commenting on the experimental studies we will examine the epidemiological studies in more detail. This will be done by first summarising the designs and main findings of the most relevant published studies and then discussing methodological issues relating to the studies taken as a whole. Finally, we will present conclusions and offer recommendations for future research.

Adult↗
PubMed1993

Effect of finasteride on serum PSA concentration in men with benign prostatic hyperplasia. Results from the North American phase III clinical trial.

Finasteride, a 5-alpha reductase inhibitor recently introduced for the treatment of symptomatic benign prostatic hyperplasia, reduces prostate size and decreases serum PSA concentration. To interpret PSA in men treated with finasteride, it is necessary to take the reduction into account. This article describes the effect of finasteride on the serum PSA concentration in the North American Phase III clinical trial and discusses implications of these findings for the interpretation of serum PSA in men treated with finasteride.

Adult↗
PubMed1993

Influence of patient age on the serum PSA concentration. An important clinical observation.

Although PSA is a most valuable tool for the practicing physician, it lacks sufficient sensitivity and specificity for detecting early prostate cancer to be the perfect tumor marker. The parameters PSAD and PSA velocity are useful attempts to make PSA a better tumor marker, but they likewise are not always reliable on an individual basis. There is now evidence from several investigations that the serum PSA concentration in healthy men without clinical evidence of prostate cancer increases with advancing age. This is primarily attributable to the concomitant increase in prostate size over the same time period. As a result, age-specific reference ranges have been determined and have the potential to make PSA a more sensitive tumor marker for men less than 60 years of age and a more specific tumor marker for men beyond 60 years of age. If one utilizes the age-specific reference ranges for serum PSA, it appears that PSAD can be eliminated as a parameter in the diagnostic evaluation of patients suspected of having prostate cancer. Thus, a new algorithm utilizing age-specific reference ranges has been developed.

Adult↗
PubMed1992

Reoperation and mortality after surgical treatment of benign prostatic hypertrophy in a large prepaid medical care program.

The incidence of reoperation and mortality after prostatectomy was studied in 8,219 men who underwent surgical treatment for benign prostatic hypertrophy between 1976 and 1987 while they were members of the Kaiser Permanente Medical Care Program, Northern California Region. The vast majority (94.5%) received transurethral prostatectomy (TURP). The cumulative 8-year probability of a second prostatectomy was 7.6% after TURP and 2.1% after open prostatectomy. The risk of mortality associated with transurethral prostatectomy relative to open prostatectomy was 1.6 (95% confidence interval 1.2, 2.1) 8 years postsurgery. The increased risk of mortality associated with transurethral prostatectomy was most prominent during the first 5 years postsurgery (relative risk 1.8, 95% confidence interval 1.3, 2.5) and declined to 1.1 (95% confidence interval 0.8, 1.6) for deaths occurring after the first 5 years. The finding of an increased risk of mortality associated with transurethral prostatectomy is consistent with other studies and is unexplained.

Aged↗
PubMed1992

Community pharmacists as immunization advocates. Cost-effectiveness of a cue to influenza vaccination.

To assess the cost-effectiveness of a cue to influenza vaccination provided by community pharmacists, a decision tree was constructed of the consequences of implementing a pharmacy-based vaccine-advocacy program, based on experience gained in an experiment involving three community pharmacies in Durham County, North Carolina. The model used morbidity and mortality assumptions derived from the infectious-disease literature and cost assumptions based on 1990-91 Medicare Part A and Part B reimbursement costs. This analysis suggests that if Medicare reimbursed pharmacists for advising 100,000 patients at risk to accept influenza vaccine through vaccine-advocacy messages, for an apparent expenditure of $110,000, the increased rate of influenza vaccinations would avert 139 hospitalizations and 63 deaths, and actually yield Medicare a net savings of $280,588. These calculations probably underestimate the benefit to society of a pharmacy-based vaccine-advocacy program, because only direct costs to the single government agency were computed and no cost was attributed to death or lost earnings.

Aged↗
PubMed1992

Incidence of migraine headache: a population-based study in Olmsted County, Minnesota.

To determine the incidence of clinically detected migraine headache in the defined population of Olmsted County, MN, 1979-1981, we screened over 6,400 patient records from several diagnostic rubrics using the unique resources of the Rochester Epidemiology Project for population-based studies. We identified 629 Olmsted County residents who fulfilled the International Headache Society's 1988 criteria for newly diagnosed migraine headache between 1979 and 1981. The overall age-adjusted incidence was 137 per 100,000 person-years for males and 294 per 100,000 person-years for females. The highest incidence in females was among those aged 20 to 24 years (689 per 100,000 person-years), and in males, the highest incidence was among those aged 10 to 14 years (246 per 100,000 person-years). From 1979 to 1981, there was a striking increase in the age-adjusted incidence in those under 45 years of age: the incidence increased 34% in women and 100% for men. This is the first population-based study of migraine incidence across all ages.

Adolescent↗