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PubMedDate not supplied

Circannual rhythms of physical fitness and tolerance of hypoxic hypoxia.

Presence of a circannual rhythm of physical fitness and tolerance of hypoxia was demonstrated. The rhythm of physical fitness had two peaks, in April and September. Using cosinor analysis the acrophase of the circannual rhythm was found to be on Aug. 10 with a 95% confidence limit (May 30-October 16), and the amplitude of the rhythm was 1.6 ml O2/kg/min with a 95% confidence limit (0.22-2.96 ml/kg/min). The circannual rhythm of hypoxia tolerance showed a similar pattern of changes. The maximum value of this rhythm was observed also in April and in autumn, its acrophase was calculated to occur on Aug. 26 with a 95% confidence limit (May 10-October 2), and its amplitude was 33.4 sec with a 95% confidence limit (10.4-56.4 sec.). An analysis of the results of physical fitness tests carried out in training camps confirmed these circannual fluctuations of physical fitness.

Adult↗
PubMed1988

Altered gastrointestinal immune response in sarcoidosis.

Because of the possible clinical association between coeliac disease and sarcoidosis, the incidence of humoral sensitivity to dietary proteins was examined in patients with sarcoidosis. Raised concentrations of circulating IgG antibodies to alpha gliadin were found in 41/99 sarcoid patients whereas antibody levels to casein, beta lactoglobulin and ovalbumin were similar to normal controls. Subsequently, a group of 26 sarcoid patients were selected for small intestinal biopsy; 11 had raised and 15 normal alpha gliadin antibody (AGA) levels. One AGA positive patient had villous atrophy consistent with coeliac disease. Intraepithelial lymphocyte (IEL) counts were raised in AGA positive (median 30; 95% confidence limits 22-46) and AGA negative (median 24; 95% confidence limits 19-32) sarcoid patients when compared with a control group (median 13.5; 95% confidence limits 10-18) p less than 0.01. Serum IgG concentrations were raised in 11/52 patients tested but there was no correlation between IgG levels and the presence of IgG antigliadin antibodies. HLA Dr typing was done in 21 of the 26 biopsied patients. The coeliac disease associated antigen Dr3 was present in eight of 21 (38%) which is very similar to the prevalence in unselected blood donors (34%). There was no significant difference in IEL counts between Dr3 positive and Dr3 negative sarcoid patients. These findings suggest that in patients with sarcoidosis, there is an altered gastrointestinal mucosal immune response, accompanied in about 40% of patients by specific sensitisation to wheat protein.

Adolescent↗
PubMed1989

Prevalence of Alzheimer's disease in a community population of older persons. Higher than previously reported.

Clinically diagnosed Alzheimer's disease and other dementing illnesses were assessed in a geographically defined US community. Of 3623 persons (80.8% of all community residents over 65 years of age) who had brief memory testing in their homes, a stratified sample of 467 persons underwent neurological, neuropsychological, and laboratory examination. Prevalence rates of Alzheimer's disease were calculated for the community population from the sample undergoing clinical evaluation. Of those over the age of 65 years, an estimated 10.3% (95% confidence limits, 8.1% and 12.5%) had probable Alzheimer's disease. This prevalence rate was strongly associated with age. Of those 65 to 74 years old, 3.0% (95% confidence limits, 0.8 and 5.2) had probable Alzheimer's disease, compared with 18.7% (95% confidence limits, 13.2 and 24.2) of those 75 to 84 years old and 47.2% (95% confidence limits, 37.0 and 63.2) of those over 85 years. Other dementing conditions were uncommon. Of community residents with moderate or severe cognitive impairment, 84.1% had clinically diagnosed Alzheimer's disease as the only probable diagnosis. These data suggest that clinically diagnosed Alzheimer's disease is a common condition and that its public health impact will continue to increase with increasing longevity of the population.

Age Factors↗
PubMed1994

Anticoagulant therapy in deep venous thrombosis. A randomized controlled study.

Ninety patients with venographically proven deep venous thrombosis(DVT) but without clinical signs of pulmonary embolism(PE) were randomized into two different treatment regimens to compare the safety and efficacy of continuous intravenous heparin and oral anticoagulant(AC) treatment versus non-AC treatment. All patients in the two treatment groups were actively mobilized from the day of admission and wore graduated compressing stockings. In the non-AC-group the patients were treated with phenylbutazone for ten days. Treatment with heparin was maintained for 6 days and oral AC treatment was given from the third day and continued for 3 months. Venography was repeated after 30 days. A perfusion-ventilation lung scan was performed on day 1-2, 10 and 60. In fifty-nine patients a revenography was performed, twenty nine in the AC-group and thirty in the non-AC group. For distal veins regression was found in nine and eight respectively (4.4% in favour of AC, 95% confidence limit 27.5% to -18.7%) and in proximal veins regression was found in five and eight, respectively (10.9% in favour of AC, 95% confidence limit 32.0% to -10.1%). No difference in lung scans was found after 10 days (0.8% in favour of AC, 95% confidence limit 21.5% to -19.9%) or after 60 days (3.3% in favour of non-AC treatment, 95% confidence limit 21.8% to -28.5%). In the AC group the incidence of bleeding complications was 8.3%. No side-effects of phenylbutazone was found. The present controlled clinical study demonstrated no effect of AC-treatment on DVT progression in actively mobilized patients wearing graduated compressing stockings when compared to a non-AC treated group receiving analgetic therapy with phenylbutazone. However, the patient population of the study is relatively small with wide confidence intervals for differences between groups. Before more general recommendations can be made, a large scale placebo-controlled study is needed to evaluate the possible effect of AC-treatment in DVT patients, who can be mobilized from the first day.

Administration, Oral↗
PubMed1986

Decline in lung liquid volume before labor in fetal lambs.

The volume of liquid in the fetal lung depends on the amount of liquid secreted across the pulmonary epithelium and the amount flowing through the trachea. Lung liquid volume (V1) and secretion rate Vs) were determined using an indicator-dilution technique, while tracheal flow rate (Vtr) was measured simultaneously with a bubble flowmeter. Least-squares regression analysis showed that in 10 chronically instrumented fetal lambs, V1 increased from 51.0 ml at 119 days to 104.6 ml at 135 days (V1 = -347.65 + 3.35 X days; 95% confidence limits on slope: 1.89-4.81) before declining to 70.2 ml at 142 days gestation (V1 = 768.8 - 4.92 X days; 95% confidence limits on slope: -2.55 to -7.30). Similarly Vs increased from 7.4 ml/h at 119 days to 16.8 ml/h at 133 days (Vs = -72.35 + 0.67 X days; 95% confidence limits on slope: 0.21-1.14), before declining to 7.1 ml/h at 142 days (Vs = 159.07 - 1.07 X days; 95% confidence limits on slope: -0.56 to -1.57). Vtr did not change significantly with gestation. We conclude that V1 increases until 135 days gestation, after which it falls substantially. This fall in volume, which occurs well before the onset of labor, results predominantly from the decline in Vs.

Animals↗
PubMedDate not supplied

Reproducibility of the knee signature system.

To assess trial-to-trial, installation-to-installation, and day-to-day effects of the Knee Signature System, we studied anterior/posterior translation measurements in six normal subjects. The protocol consisted of testing both knees on 6 days with three installations per day and three trials per installation. We recorded anterior, posterior, and total anterior/posterior translation at +/- 20 and +/- 40 pounds of force at 30 degrees of flexion. Additionally, after measuring anterior/posterior translation during passive knee extension, active extension, and active extension with 15 pounds of weight at the ankle, we calculated the difference in anterior translation at 30 degrees of flexion between each of these three conditions. We analyzed the size of the effects and computed 90% confidence limits using analysis of variance. Means and 90% confidence limits for total anterior/posterior translation measured at +/- 20 pounds of force were: right knee, 6.8 +/- 2.3; left knee, 8.2 +/- 2.0; and right/left difference, 1.5 +/- 2.7 mm. Left knee translation means were significantly greater than right knee means in all tests. Day-to-day effects, while statistically significant for right and left knee measurements, showed no significant effects for right/left differences. Trial-to-trial and installation-to-installation effects were not significant for any parameter. Right/left differences during knee extension testing were smaller than for the stress test, measuring 0.1 mm or less, but confidence limits were larger, being +/- 3.7 mm for active extension-passive knee extension, +/- 1.5 mm for 15 pounds of weight at the ankle-active extension, and +/- 4.6 mm for 15 pounds of weight at the ankle-passive knee extension. Active extension produced 6.3 mm more anterior translation at 30 degrees of flexion than passive extension.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Malignant lymphoma and multiple myeloma linked with agricultural occupations in a New Zealand Cancer Registry-based study.

Mortality studies have indicated that workers in agriculture and forestry may be at increased risk of developing malignant lymphoma and multiple myeloma. The authors report the findings from a case-control study of 734 male malignant lymphoma and multiple myeloma patients (International Classification of Diseases (ICD) 200-203) registered with the New Zealand Cancer Registry in the period 1977-1981 and aged 20 years or more at time of registration. Controls also were males chosen from the cancer registry with four controls per case, matched on age and year of registration. The case group contained a significant excess of the occupational category involving agriculture and forestry (odds ratio = 1.25, 95% confidence limits = 1.00, 1.56). This excess was almost entirely among those aged less than 65 years at time of registration (odds ratio = 1.45, 95% confidence limits = 1.08, 1.95), particularly among patients with multiple myeloma (ICD 203) (odds ratio = 2.22, 95% confidence limits = 1.31, 3.75) and the category including nodular lymphoma, mycosis fungoides, and unspecified non-Hodgkin's lymphoma (ICD 202) (odds ratio = 1.76, 95% confidence limits = 1.03, 3.02). Mortality from malignant lymphoma and multiple myeloma increased significantly during the period 1955-1979.

Adult↗
PubMed2005

Toward diagnostic and phenotype markers for genetically transmitted speech delay.

Converging evidence supports the hypothesis that the most common subtype of childhood speech sound disorder (SSD) of currently unknown origin is genetically transmitted. We report the first findings toward a set of diagnostic markers to differentiate this proposed etiological subtype (provisionally termed speech delay-genetic) from other proposed subtypes of SSD of unknown origin. Conversational speech samples from 72 preschool children with speech delay of unknown origin from 3 research centers were selected from an audio archive. Participants differed on the number of biological, nuclear family members (0 or 2+) classified as positive for current and/or prior speech-language disorder. Although participants in the 2 groups were found to have similar speech competence, as indexed by their Percentage of Consonants Correct scores, their speech error patterns differed significantly in 3 ways. Compared with children who may have reduced genetic load for speech delay (no affected nuclear family members), children with possibly higher genetic load (2+ affected members) had (a) a significantly higher proportion of relative omission errors on the Late-8 consonants; (b) a significantly lower proportion of relative distortion errors on these consonants, particularly on the sibilant fricatives /s/, /z/, and //; and (c) a significantly lower proportion of backed /s/ distortions, as assessed by both perceptual and acoustic methods. Machine learning routines identified a 3-part classification rule that included differential weightings of these variables. The classification rule had diagnostic accuracy value of 0.83 (95% confidence limits = 0.74-0.92), with positive and negative likelihood ratios of 9.6 (95% confidence limits = 3.1-29.9) and 0.40 (95% confidence limits = 0.24-0.68), respectively. The diagnostic accuracy findings are viewed as promising. The error pattern for this proposed subtype of SSD is viewed as consistent with the cognitive-linguistic processing deficits that have been reported for genetically transmitted verbal disorders.

Child, Preschool↗
PubMed2002

Efficacy of albendazole and levamisole against gastrointestinal nematodes of sheep and goats in Morogoro, Tanzania.

A study was conducted to determine the efficacy of albendazole after it had been withdrawn from use due to the development of resistant strains of nematodes about ten years ago. The study also aimed to determine the present efficacy of levamisole, which had been recommended to replace albendazole. On one farm, the sheep and goats were divided into two groups, one group of each serving as the untreated control, while the other was treated with levamisole. The sheep on the other farm were divided into three groups, one serving as the untreated control group, the second being treated with levamisole and the third being treated with albendazole. Faecal samples were collected one day before treatment, and again 10 days after treatment. Anthelmintic efficacy was determined by the faecal egg count reduction test. Ten days after treatment, the sheep treated with levamisole on the first farm had a 98% reduction in faecal egg count, with a 95% confidence limit of 76%. The goats on the same farm had a 97% reduction in faecal egg count, with a 95% lower confidence limit of 81%. At the second farm, 10 days after treatment, sheep treated with levamisole had a 99.4% reduction in faecal egg count, with a 95% lower confidence limit of 88.9%, whereas the sheep treated with albendazole only had a 59.4% reduction in faecal egg count, with a 95% lower confidence limit of -19.6%. The study indicated that the gastrointestinal nematodes of sheep at the Department of Animal Science and Production farm were still resistant to albendazole about ten years after this anthelmintic had been withdrawn from use. A reduced efficacy of levamisole was suspected.

Albendazole↗
PubMed2003

[Integrated evaluation on system reliability of a space metabolism simulation device].

OBJECTIVE: To define the lower confidence limit of the system reliability of the space metabolism simulation device by using the test data of the comprising units in their development phases. METHOD: A new method for defining the environmental conversion factors of failure times has been given basing on the AMSAA model, and the MTBF point evaluated values and lower confidence limits of the units were defined, at last, the lower confidence limit of the system reliability was obtained using L-M method. RESULT: The lower confidence limit of the system reliability under confidence level of 0.8 is 0.9281, which is consistent with the result obtained by the classic system reliability evaluation method. CONCLUSION: Integrated system reliability evaluation using the proposed method can well satisfy the need in engineering.

Equipment Design↗
PubMed1991

Right ventricular aneurysm: a new prognostic indicator after a first acute myocardial infarction.

The prognostic implication of a right ventricular aneurysm after a first acute myocardial infarction (AMI) was assessed on a series of 137 AMI patients 12 of whom had a right ventricular aneurysm detected at radionuclide angiocardiography. The follow-up lasted 36 months. Mortality was 50 and 18.4% in patients with and without right ventricular aneurysm, respectively (p less than 0.02). Groups did not differ in age, male-to-female ratio, AMI site, left ventricular ejection fraction (LVEF), peak filling rate (PFR), left ventricular size. A multivariate logistic analysis showed that only three out of ten clinical and functional variables qualified to be independent predictors of death: right ventricular aneurysm (odd ratio = 2.48, confidence limits = 1.21-4.98), LVEF less than 52% (odd ratio = 1.91, confidence limits = 1.03-3.48), abnormal terminal P wave forces (odd ratio = 1.72, confidence limits = 1.07-2.75). The analysis of single case histories did not provide a clue to clarify the reasons accounting for the negative prognostic implication of a right ventricular aneurysm. In conclusion, a significant positive relationship between right ventricular aneurysm and mortality after AMI has been demonstrated; further study is needed to clarify the relevant mechanisms.

Aged↗
PubMed1987

Surgical experience with the modified Fontan procedure.

During a 10 year period 109 patients (3 months to 47 years old) underwent modifications of the Fontan procedure for repair of classic tricuspid atresia (TA) (n = 58), univentricular atrioventricular connection (UVH) (n = 38), or other complex malformations (CM) (n = 13). Among patients with TA, an atriopulmonary connection was used in 19 (33%) and incorporation of the right ventricle with the Björk modification and with a right atrial-to-right ventricular valved conduit was used in 20 (34%) and in 19 (33%), respectively. Three of the latter 19 also underwent a combined Fontan-switch procedure. The hospital mortality rate was 13.8% (70% confidence limits, 9.3% to 18.3%) for patients with TA, 28.9% (70% confidence limits, 21.3% to 37.0%) for patients with UVH, and 7.7% (70% confidence limits, 0% to 15.4%) for patients with CM. Multivariate analysis identified with the following variables as risk factors for both early and late deaths: diagnosis of UVH, previous pulmonary artery banding (PAB), and postrepair right atrial pressure, and, in patients with TA, the use of a direct atriopulmonary connection (all variables, p less than .05). Morphometric lung biopsy scores were not different in patients with PAB, implicating the role of ventricular hypertrophy rather than pulmonary vascular disease as the mechanism for the adverse effect of PAB. Right atrial pressure was a predictor of serious late cardiac symptoms, which were present in 10% of eligible patients (p = .032). This review demonstrates a survival advantage with modifications of the Fontan procedure that incorporate the hypoplastic right ventricle in patients with TA.(ABSTRACT TRUNCATED AT 250 WORDS)

Actuarial Analysis↗
PubMedDate not supplied

Serum micronutrients and the subsequent risk of cervical cancer in a population-based nested case-control study.

A nested case-control study was conducted in Washington County, MD, to determine whether low serum micronutrients are related to the subsequent risk of cervical cancer. Among the 15,161 women who donated blood for future cancer research during a serum collection campaign in 1974, 18 developed invasive cervical cancer and 32 developed carcinoma in situ during the period January 1975 through May 1990. For each of these 50 cases, two matched controls were selected from the same cohort. The frozen sera of the cases and their matched controls were analyzed for a number of nutrients. The mean serum levels of total carotenoids, alpha-carotene, beta-carotene, cryptoxanthin, and lycopene were lower among cases than they were among controls. When examined by tertiles, the risk of cervical cancer was significantly higher among women in the lower tertiles of total carotenoids (odds ratio 2.7; 95% confidence limit, 1.1-6.4), alpha-carotene (odds ratio, 3.1; 95% confidence limit, 1.3-7.6), and beta-carotene (odds ratio, 3.1; 95% confidence limit, 1.2-8.1) as compared to women in the upper tertiles and the trends were statistically significant. Cryptoxanthin was significantly associated with a lower risk of cervical cancer when examined as a continuous variable. Retinol, lutein, alpha- and gamma-tocopherol, and selenium were not related to cervical cancer risk. Smoking was also strongly associated with cervical cancer. These findings are suggestive of a protective role for total carotenoids, alpha-carotene and beta-carotene in cervical carcinogenesis and possibly for cryptoxanthin and lycopene as well.

Adult↗
PubMed1998

Alcohol and mortality: is there a U-shaped relation in elderly people?

OBJECTIVE: to assess the relation between alcohol intake and mortality among seven cohorts of middle-aged and elderly Danes. DESIGN: Prospective population study with baseline assessment of alcohol- and tobacco consumption, educational level and body mass index, and a mean of 11.5 years follow-up of mortality. SUBJECTS: 16304 men and women aged 50 years or more. MAIN OUTCOME MEASURE: number and time of deaths from 1974 to 1995 as ascertained by the national central person register. RESULTS: the effect of alcohol intake on mortality did not differ between middle-aged (50-64 years, mean = 56.6 years) and elderly subjects (>64 years old, mean = 69.9 years). There was a U-shaped risk function in both age groups, which persisted also when adjusting for age, sex, smoking habits, level of education and body mass index. Abstaining women had a relative risk of 1.29 (95% confidence limits 1.17-1.42) as compared with light drinkers (1-6 (drinks per week), while the relative risk for abstaining men was 1.22 (95% confidence limits; 1.08 to 1.37) as compared with light drinkers. Heavy drinking women (>28 drinks per week) had a relative risk of 1.23 (95% confidence limits; 0.85 to 1.78) and heavy drinking men (more than 69 drinks per week) had a relative risk of 2.11 (95% confidence limits 1.66-2.69), both compared with light drinkers. CONCLUSION: among the middle-aged and elderly women and men, a light alcohol intake is associated with lower mortality than abstention or heavy drinking.

Aged↗
PubMed1984

Second primaries in children with central nervous system tumors.

Among 670 children diagnosed with central nervous system tumors before age 20 and recorded in the Connecticut Tumor Registry, nine had a second neoplasm as well. From known age-specific and year-specific cancer incidence figures for Connecticut, the expected number of second neoplasms for the series of 670 is 0.99; therefore the relative risk is 9.1 (95% confidence limits: 4.0, 17.3). Three patients developed two central nervous system tumors, while 0.16 were expected, giving a relative risk of 19 (95% confidence limits: 3.8, 55). Six patients developed two neoplasms in childhood, versus 0.66 expected; the relative risk of this event is 9.1 (95% confidence limits: 3.3, 20). In four cases of lapse in time between the diagnosis of the first and second tumor, the first tumor had been treated with radiation. Five cancers occurred in parents or siblings of these nine patients, versus 0.91 expected; the relative risk is 5.5 (95% confidence limits: 1.2, 10.0). Three of these relatives had leukemia, while only 0.04 cases were expected (relative risk = 75). We conclude that not only is a child with CNS cancer at increased risk for other cancers, but such a child with two cancers is often part of a familial cluster with increased risk of cancer.

Adenoma, Chromophobe↗
PubMed1999

Survival analysis: caveats and pitfalls.

BACKGROUND: Survival analysis in clinical studies is important to assess the effectiveness of a given treatment and to understand the effect of various disease characteristics. A number of methods exist to estimate the survival rate and its standard error. However, one cannot be certain that these methods have been handled appropriately. The widespread use of computers has made it possible to carry out survival analysis without expert guidance, but using inappropriate methods can give rise to erroneous conclusions. The majority of the biomedical journals now recommend that a statistical review of each manuscript should be carried out by an experienced bio-statistician, in addition to obtaining expert referees' comments on the article. The problem is compounded in papers from third-world countries where bio-statisticians may not be available in all institutions to guide clinicians as to the selection of proper techniques. METHODS: The present paper deals with the various techniques of survival analysis and their interpretation, using a modal data set of malignant upper-aerodigestive tract melanoma patients treated in the Regional Cancer Centre, Trivandrum since 1982. RESULTS: The Kaplan-Meier method was found to be the most suitable for survival analysis. The median survival time is a better method of summarizing data than the mean. Rothman's method of estimation of the confidence limit is better than Peto's method as the confidence limit for survival probability tends to go beyond the range of 0-1.0 when calculated by Peto's method, especially when the sample size is small. CONCLUSION: The results from the present study suggest that survival analysis should be carried out by the Kaplan-Meier method. The median survival time should be provided wherever possible, rather than relying on mean survival. Confidence limits should be calculated as a measure of variability. A suitable rank test should be used to compare two or more survival curves, rather than a Z-test. Stratified analysis and Cox's model, when stratified analysis fails, can be used to define the impact of prognostic factors on survival.

Confidence Intervals↗
PubMed1986

Detection of nocturnal hypoglycemia in insulin-treated diabetics by a skin temperature--skin conductance meter.

The efficacy and credibility of a skin temperature--skin conductance meter (Teledyne Sleep Sentry) for detecting hypoglycemia was studied during night-time in 22 adult insulin-treated diabetics. Capillary blood glucose concentration was measured 99 times (when the alarm sounded, in case of hypoglycemic symptoms, and at 3 a.m.). Hypoglycemia was defined as a capillary blood glucose concentration of less than or equal to 3 mmol/l. Blood glucose was measured 61 times in connection with sounding of the alarm and 38 times without the alarm sounding. At 3 a.m. the Sleep Sentry sounded the alarm 22 times, of which hypoglycemia was present 6 times giving a diagnostical specificity or diagnostical true positive rate of 0.27 (95% confidence limits 0.11-0.50). In 35 of 38 cases of no alarm the blood glucose was greater than 3 mmol/l, giving a diagnostical sensitivity of 0.92 (95% confidence limits 0.79-0.98). The Sleep Sentry sounded the alarm in 6 of 9 cases of hypoglycemia, giving a nosological sensitivity of 0.67 (95% confidence limits 0.30-0.93). The Sleep Sentry did not sound the alarm in 35 of 51 cases of non-hypoglycemia, giving a nosological specificity of 0.69 (95% confidence limits 0.54-0.81). In other words, the Sleep Sentry detects about 2/3 of blood glucose values less than or equal to 3 mmol/l, but in addition it sounds a false alarm in 2/3 of the cases.

Adolescent↗
PubMed1999

Survival analysis: caveats and pitfalls.

BACKGROUND: Survival analysis in clinical studies is important to assess the effectiveness of a given treatment and to understand the effect of various disease characteristics. A number of methods exist to estimate the survival rate and its standard error. However, one cannot be certain that these methods have been handled appropriately. The widespread use of computers has made it possible to carry out survival analysis without expert guidance, but using inappropriate methods can give rise to erroneous conclusions. The majority of the biomedical journals now recommend that a statistical review of each manuscript should be carried out by an experienced bio-statistician, in addition to obtaining expert referees' comments on the article. The problem is compounded in papers from third-world countries where bio-statisticians may not be available in all institutions to guide clinicians as to the selection of proper techniques. METHODS: The present paper deals with the various techniques of survival analysis and their interpretation, using a modal data set of malignant upper-aerodigestive tract melanoma patients treated in the Regional Cancer Centre, Trivandrum since 1982. RESULTS: The Kaplan-Meier method was found to be the most suitable for survival analysis. The median survival time is a better method of summarizing data than the mean. Rothman's method of estimation of the confidence limit is better than Peto's method as the confidence limit for survival probability tends to go beyond the range of 0-1.0 when calculated by Peto's method, especially when the sample size is small. CONCLUSION: The results from the present study suggest that survival analysis should be carried out by the Kaplan-Meier method. The median survival time should be provided wherever possible, rather than relying on mean survival. Confidence limits should be calculated as a measure of variability. A suitable rank test should be used to compare two or more survival curves, rather than a Z-test. Stratified analysis and Cox's model, when stratified analysis fails, can be used to define the impact of prognostic factors on survival.

Digestive System Neoplasms↗