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At least 19 recordsLinked to original sources
PubMed2003

[Can nomograms derived in the U.S. applied to German patients? A study about the validation of preoperative nomograms predicting the risk of recurrence after radical prostatectomy].

In patients suffering from prostate cancer, preoperative nomograms, which predict the risk of recurrence may provide a helpful tool in regard to the counselling and planning of an appropriate therapy. The best known nomograms were published by the Baylor College of Medicine, Houston and the Harvard Medical School, Boston. We investigated these nomograms derived in the U.S. when applied to German patients. Data from 1003 patients who underwent radical prostatectomy at the University-Hospital Hamburg were used for validation. Nomogram predictions of the probability for 2-years (Harvard nomogram) and 5-years (Kattan nomogram) freedom from PSA recurrence were compared with actual follow-up recurrence data using areas under the receiver-operating-characteristic curves (AUC). The recurrence free survival after 2 and 5 years was 78% and 58%, respectively. The AUC of the Harvard nomogram predicting 2-years probability of freedom from PSA recurrence was 0.80 vs. Kattan-Nomogram 5-years prediction of 0.83. Thereby, the Kattan nomogram showed a significant higher predictive accuracy (p=0.0274). For that reason preoperative nomograms derived in the U.S. can be applied to german patients. However, we would recommend the utilization of the Kattan nomogram due to its higher predictive accuracy.

Biomarkers, Tumor↗
PubMed2003

Fetal transcerebellar diameter nomogram in singleton gestations with special emphasis in the third trimester: a comparison with previously published nomograms.

OBJECTIVE: This study was undertaken to construct an institution-specific transverse cerebellar (transcerebellar) diameter nomogram with special emphasis in the third trimester and to compare its ability to predict gestational age with previously published nomograms. STUDY DESIGN: A cross-sectional nomogram was constructed using transcerebellar diameter measurements in 24,026 well-dated singleton fetuses by using linear regression models. Third-trimester measurements from 2,010 fetuses were included. The performance of previously established transcerebellar diameter nomograms for predicting gestational age was assessed in our population to determine comparability between nomograms. RESULTS: Interobserver and intraobserver variabilities in the second and third trimesters were 3.1% to 3.7% and 3.4% to 3.8%, respectively. Between 14 and 27 weeks' gestation, there were no clinically important differences between our nomogram and those previously published in terms of the predicted gestational age. However, predicted gestational age in the third trimester was considerably different by using our nomogram by 1 to 2 weeks from 28 to 30 weeks and by 4 to 6 weeks after 32 weeks. CONCLUSION: Transcerebellar measurements had a similar relationship with gestational age across previously published nomograms before 28 weeks. However, clinically significant differences in predicting gestational age appear later, especially after 32 weeks. These findings suggest that this new nomogram may be particularly useful for accurate dating of pregnancies in the third trimester.

Cerebellum↗
PubMed1993

The weight-based heparin dosing nomogram compared with a "standard care" nomogram. A randomized controlled trial.

OBJECTIVE: To determine whether an intravenous heparin dosing nomogram based on body weight achieves therapeutic anticoagulation more rapidly than a "standard care" nomogram. DESIGN: Randomized controlled trial. SETTING: Two community teaching hospitals in Phoenix, Arizona, and Rochester, New York. PARTICIPANTS: One hundred fifteen patients requiring intravenous heparin treatment for venous or arterial thromboembolism or for unstable angina. INTERVENTION: Patients were randomized to the weight-based nomogram (starting dose, 80 units/kg body weight bolus, 18 units/kg per hour infusion) or the standard care nomogram (starting dose, 5000-unit bolus, 1000 units per hour infusion). Activated partial thromboplastin time (APTT) values were monitored every 6 hours, and heparin dose adjustments were determined by the nomograms. MEASUREMENTS: Activated partial thromboplastin times were measured using a widely generalizable laboratory method. The primary outcomes were the time to exceed the therapeutic threshold (APTT > 1.5 times the control) and the time to achieve therapeutic range (APTT, 1.5 to 2.3 times the control). Bleeding complications and recurrent thromboembolism were also compared. RESULTS: Kaplan-Meier curves for the primary outcomes favored the weight-based nomogram (P < 0.001 for both). In the weight-based heparin group, 60 of 62 patients (97%) exceeded the therapeutic threshold within 24 hours, compared with 37 of 48 (77%) in the standard care group (P < 0.002). Only one major bleeding complication occurred (in a standard care patient). Recurrent thromboembolism was more frequent in the standard care group; relative risk, 5.0 (95% CI, 1.1 to 21.9). CONCLUSIONS: The weight-based heparin nomogram is widely generalizable and has proved to be effective, safe, and superior to one based on standard practice.

Angina, Unstable↗
PubMed1998

Use of a heparin nomogram for treatment of patients with venous thromboembolism in a community hospital.

BACKGROUND: The application of a heparin dosing nomogram in the treatment of patients with venous thromboembolism resulted in improvement of heparin therapy in clinical research settings. In 1992 a heparin nomogram was introduced in our hospital, which is a community hospital where anticoagulant therapy is supervised by the attending physicians. We studied whether comparable improvements were achieved in such a non-surveyed clinical setting. METHODS: Patients were identified from computerized discharge records, and classified into a pre-nomogram (discharged in 1990 or 1991) and a nomogram patient group (discharged in 1993 or 1994). The use of the nomogram was encouraged but the application remained on a voluntary basis. Since the definition of the target APTT range was different in the pre-nomogram period as compared to the nomogram period, a formal analysis of pre- and post-nomogram results was not considered justified. RESULTS: The APTT ratio, six hours after the start of heparin treatment, was below the predefined lower limit in 72% of 127 patients in the pre-nomogram group and in 13% of 127 patients in the nomogram group. During 1043 days heparin therapy in the nomogram group the morning APTT ratio was subtherapeutic in 8%. In 58% of all APTT results the physician responded according to the nomogram. The subsequent APTT was in the target range in 64% of the cases compared to 31% if the adjustement was not performed according to the nomogram (P<.0001). Major bleeding episodes occurred in 3.1% in the pre-nomogram period and in 0.7% in the nomogram period. CONCLUSION: The present study shows that the introduction of a heparin dosing nomogram in a non-research clinical setting results in more adequate heparin anticoagulation with low risks of bleeding.

Adult↗
PubMedDate not supplied

A validation of two preoperative nomograms predicting recurrence following radical prostatectomy in a cohort of European men.

Kattan et al. at Baylor College of Medicine and D'Amico et al. at Harvard Medical School have each developed preoperative nomograms for prostate cancer recurrence after radical prostatectomy based on readily available clinical variables. Calibration and validation of those tools was achieved using North American patient cohorts, and their validity has not yet been shown in patients from other continents. We investigated the predictive accuracy of these nomograms when applied to European men with localized prostate cancer. Clinical data from patients who underwent radical prostatectomy at the University-Hospital Hamburg and fitted the respective derivation criteria were used for external validation (n = 1003 for the Kattan-Nomogram, n = 932 men for the D'Amico-Nomogram). Nomogram predictions of the probability for 2-years and 5-years freedom from recurrence predicted by the D'Amico-Nomogram and the Kattan-Nomogram respectively were compared with actual follow-up. The predictive accuracy of the nomograms was tested using areas under the receiver-operating-characteristic curves (AUC). The D'Amico-Nomogram AUC predicting 2-years probability of freedom from PSA recurrence was 0.80 vs. Kattan-Nomogram 5-years prediction with an AUC of 0.83. Using the 932 patients who exactly fit the derivation criteria of both nomograms, the predictive accuracy of the Kattan-Nomogram was 0.81. The superiority in predictive accuracy of the Kattan-Nomogram was statistically significant (p = 0.0274) but of unclear clinical significance. The two nomograms predicted recurrence with similar accuracy when applied to men diagnosed with localized prostate cancer in Germany. The high predictive accuracy of both nomograms demonstrates that these predictive tools derived in the U.S. can be applied to non-U.S. patients.

Cohort Studies↗
PubMed2002

The Anderson nomograms for permanent interstitial prostate implants: a briefing for practitioners.

PURPOSE: The objective of this report is to re-evaluate the role of the Anderson nomograms in treatment planning for permanent prostate implants. The incentive for revisiting this topic concerns three issues: (1) Although nomograms continue to be used in many centers for ordering seeds, few centers use them during treatment planning; (2) Whereas nomograms were designed to deliver a minimum peripheral dose for a uniform distribution of seeds in the gland, many practitioners use peripheral seed loading patterns to reduce urethral toxicity; and (3) As preoperative and intraoperative treatment planning is becoming standard, the apparent role of nomograms is diminished. The nomogram method is reviewed in terms of: (1) total activity predicted, (2) target coverage (as planned in the operating room and as calculated from postimplant computed tomography studies), and (3) reproducibility (i.e., patient-to-patient and planner-to-planner variability). In each case, the computer-optimization system for intraoperative planning currently in use at our institution was taken as the "gold standard." METHODS AND MATERIALS: We compared for the same patient the results of nomogram planning to those yielded by genetic algorithm (GA) optimization in terms of total activity predicted (n = 20 cases) and percent target coverage (n = 5 cases). Furthermore, we examined retrospectively the dosimetry of 61 prostate implants planned with the GA (n = 27) and the current implementation of Anderson nomograms (n = 34). RESULTS: Nomogram predictions of the total activity required are in good agreement (within 10%) with the GA-planned activity. However, computer-optimized plans consistently yield superior plans, as reflected in both pre- and postimplant analyses. We find also that user (specifically, treatment planner) implementation of the nomograms may be a major source of variability in nomogram planning-a difficulty to which robust computer optimization is less prone. CONCLUSIONS: Nomograms continue to be useful tools for predicting the total required activity for volume implants, and thus for performing an independent check of this quantity. Not unexpectedly, computer optimization remains the preferred planning method. Generally, nomogram-guided implants do not incorporate structures other than the treatment volume into the planning process. Further yet, they deliver a lower dose than that prescribed and result in greater variability among plans than computer-optimized treatments. In summary, nomograms (1) remain an efficient quality assurance tool for computer-generated plans, (2) serve as a good predictor of the number of seeds required for ordering purposes, and (3) provide a simple and dependable backup planning method in case the intraoperative planning system fails.

Algorithms↗
PubMed1998

Neural network computer program to determine photorefractive keratectomy nomograms.

PURPOSE: To evaluate a commercially available neural network program for calculation of photorefractive keratectomy treatment nomograms. SETTING: University referral refractive surgery clinic. METHODS: PRK/LASIK Brain, a commercial neural network computer program, was trained using the demographics, preoperative clinical data, surgical parameters, and 1 year postoperative clinical data of 44 patients treated with a Summit Technology excimer laser using a 5.0 mm optical zone. The neural-network derived nomogram was compared with the standard treatment nomogram for each patient. The relative contribution of age, sex, keratometry, and intraocular pressure (IOP) to the predicted nomograms was also assessed. RESULTS: Nomograms produced by the neural network were qualitatively similar to the standard nomogram. The sequence of data entry during training affected the network's predictions. Entry ordered by outcome (as opposed to entry by chronological order) yielded a nomogram that was more consistent with the standard nomogram. However, both outcome- and chronologically ordered network-derived nomograms diverged from the standard nomogram in individual patients, including a subset for whom use of the standard nomogram yielded desired refractive results (within 0.25 diopter of emmetropia). Further analysis of the neural-network-derived nomograms revealed marked sensitivity to sex, age, keratometry readings, and IOP. CONCLUSIONS: Neural networks offer a potential means of individualizing treatment nomograms, to account for patient demographics, preoperative examination, surgeon style, and equipment bias. However, a data set of 44 patients was not sufficient to train the PRK/LASIK Brain network to accurately predict treatment parameters in individual cases in the training set. A larger training set or a different learning algorithm may be required to improve the neural network's performance.

Adult↗
PubMed1997

Reevaluation of a weight-based heparin dosing nomogram: is institution-specific modification necessary?

OBJECTIVE: To compare a heparin dosing nomogram using an initial infusion rate of 18 units/kg/h with physician-directed heparin prescribing and with a modified version of the nomogram adjusted for institution-specific data. METHODS: During consecutive phases of this cohort study, patients' intravenous heparin therapies were initiated and adjusted by using one of the following three methods: (1) physician-directed dosing, (2) a body weight-based dosing nomogram with an initial infusion rate of 18 units/kg/h, and (3) a body weight-based dosing nomogram with an initial infusion rate determined by the median dose of heparin (in units/kg/h) required to achieve therapeutic activated partial thromboplastin times (aPTTs) during the first two phases. The time required to achieve therapeutic aPTTs as well as the percentage of initial aPTTs in the therapeutic range were compared for the three phases. RESULTS: The heparin dosing nomogram in which the initial infusion rate was adjusted for our individual institution resulted in a statistically shorter median time until aPTTs were in the therapeutic range than did either the physician-directed dosing or unmodified nomogram groups (6.1 h in the modified nomogram group, 10.5 h in the physician-directed group, 21.5 h in the unmodified nomogram group; p < 0.05 for all differences). Use of the institution-specific nomogram resulted in the greatest percentage of initial aPTTs in the therapeutic range (84% in the 13 units/kg/h nomogram group vs. 47% in the physician-directed group and 18% in the 18 units/kg/h nomogram group; p < 0.05 for all differences). CONCLUSIONS: Use of a heparin dosing nomogram with an initial infusion rate of 18 units/kg/h resulted in prolongation of the time to reach therapeutic aPTTs. By modifying the nomogram for use at an individual institution, we reduced the time to achieve therapeutic range of aPTTs while still reducing the likelihood of excessive anticoagulation of patients.

Aged↗
PubMed2005

Validation of an insulin infusion nomogram for intensive glucose control in critically ill patients.

STUDY OBJECTIVE: To evaluate the effectiveness, safety, and associated patient outcomes of a simplified, nurse-directed insulin nomogram designed to achieve intensive blood glucose level control (target range 90-144 mg/dl). DESIGN: Prospective study with a retrospective control group. SETTING: A medical-surgical intensive care unit (ICU) in a quaternary care, university-affiliated hospital in an urban center. PATIENTS: Eighty-six critically ill adult patients (aged>or=18 yrs) requiring blood glucose control, with 42 in the retrospective control group and 44 in the prospective nomogram group. INTERVENTION: Control patients received insulin subcutaneously or intravenously based on ad hoc insulin sliding scales; nomogram patients received intravenous insulin at a rate specified by the nomogram, based on capillary blood glucose levels measured at the bedside. MEASUREMENTS AND MAIN RESULTS: Insulin infusion in the prospective patient group was titrated by the bedside nurse based on a predefined nomogram to attain the target blood glucose level. The retrospective control group was used as a comparison to assess the safety and effectiveness of the nomogram. Fewer patients in the nomogram (32%) than control (67%) group had a diagnosis of diabetes mellitus on admission. Overall, blood glucose levels in the nomogram group were within the target range 52% of the time versus 20% in the control group (p<0.001). Morning blood glucose levels were significantly lower compared with the control group (mean+/-SD 128+/-32 vs 176+/-50 mg/dl, p<0.001). Nomogram patients achieved target blood glucose levels faster than control patients (median 15 vs 66 hrs, p<0.0001). This improved blood glucose control remained statistically significant after adjusting for baseline differences in diabetes status. Hyperglycemia occurred less often in the nomogram than the control group (14% vs 53%, p<0.0001), and hypoglycemia occurred more often (3.8% vs 2.2%, p=0.004). The frequency of severe hypoglycemia was similar in both groups (0.2% vs 0.4%, p=NS). Such control required slightly more blood glucose checks/day in the nomogram group (7.1+/-1.5 vs 5.8+/-1.1, p<0.001). No significant reduction was observed in duration of vasopressor or antibiotic therapy or in length of stay in the ICU. CONCLUSION: This study demonstrated that intensive blood glucose control is achievable using a nurse-directed nomogram. This improved control was achieved, regardless of diabetes status of the patient, without substantially compromising safety or increasing resource use.

Aged↗
PubMed2002

Validation study of the accuracy of a postoperative nomogram for recurrence after radical prostatectomy for localized prostate cancer.

PURPOSE: A postoperative nomogram for prostate cancer was developed at Baylor College of Medicine. This nomogram uses readily available clinical and pathologic variables to predict 7-year freedom from recurrence after radical prostatectomy. We evaluated the predictive accuracy of the nomogram when applied to patients of four international institutions. PATIENTS AND METHODS: Clinical and pathologic data of 2,908 patients were supplied for validation, and 2,465 complete records were used. Nomogram-predicted probabilities of 7-year freedom from recurrence were compared with actual follow-up in two ways. First, the area under the receiver operating characteristic curve (AUC) was calculated for all patients and stratified by the time period of surgery. Second, calibration of the nomogram was achieved by comparing the predicted freedom from recurrence with that of an ideal nomogram. For patients in whom the pathologic report does not distinguish between focal and established extracapsular extension (an input variable of the nomogram), two separate calculations were performed assuming one or the other. RESULTS: The overall AUC was 0.80 when applied to the validation data set, with individual institution AUCs ranging from 0.77 to 0.82. The predictive accuracy of the nomogram was apparently higher in patients who were operated on between 1997 and 2000 (AUC, 0.83) compared with those treated between 1987 and 1996 (AUC, 0.78). Nomogram predictions of 7-year freedom from recurrence were within 10% of an ideal nomogram. CONCLUSION: The postoperative Baylor nomogram was accurate when applied at international treatment institutions. Our results suggest that accurate predictions may be expected when using this nomogram across different patient populations.

Adult↗
PubMed2002

Comparison of a nomogram and physician-adjusted dosage of warfarin for prophylaxis against deep-vein thrombosis after arthroplasty.

BACKGROUND: Warfarin is an effective agent for prophylaxis against deep-vein thrombosis following total hip or knee arthroplasty. However, management with warfarin in the postoperative setting is problematic because of the need for anticoagulant monitoring. We developed a nomogram for the dosing of warfarin that was specific for joint arthroplasty. The objective of this study was to compare the performance of this nomogram with that of physician-adjusted dosing of warfarin for patients undergoing total hip or knee arthroplasty. METHODS: The study involved two cohort trials. The historical control group consisted of 1024 patients who underwent total hip or knee arthroplasty during the course of a clinical trial (the Post-Arthroplasty Screening Study [PASS]) in which all warfarin dose adjustments were made by two hematologists. The first dose of warfarin was given on the evening of the surgery, and the warfarin dose was adjusted daily on the basis of the international normalized ratio and was discontinued at the time of discharge from the hospital. In the PASS study, the dosage of warfarin was designed to prolong the international normalized ratio to 1.7 by postoperative day 4 and to maintain it between 1.8 and 2.5 until discharge from the hospital. Subsequently, a warfarin nomogram was developed on the basis of the dose adjustments used in the PASS study, and it was used prospectively to manage a cohort of 729 patients undergoing total hip or knee arthroplasty. In the nomogram cohort, the initial dose of warfarin was given on the evening of the surgery. Both cohorts were followed for twelve weeks after the surgery to determine if any venous thromboembolic complications had developed. RESULTS: The nomogram cohort and the control cohort had similar daily doses of warfarin (mean, 3.2 versus 3.3 mg) and levels of international normalized ratio on postoperative day 4 (mean, 1.9 versus 1.9) (p > 0.2). The average number of days to achieve an international normalized ratio of >1.7 was 4.0 for the nomogram cohort compared with 4.3 for the control cohort (p = 0.01). The percentage of days that the international normalized ratio was between 1.8 and 2.5 was 61% for the nomogram cohort and 58% for the control cohort (p < 0.01), and the percentage of days that the international normalized ratio was >3.0 was only 6.5% for the nomogram cohort and 6.0% for the control cohort (p > 0.2). Eighty-two percent of the patients managed with the nomogram achieved an international normalized ratio of >1.7 by the time of discharge from the hospital compared with 92% in the control cohort (p = 0.01). In the three-month follow-up period, a deep-vein thrombosis or a nonfatal pulmonary embolism developed in nineteen patients (2.6%; 95% confidence interval, 1.6% to 4.0%) in the nomogram cohort compared with fourteen patients (1.4%; 95% confidence interval, 0.7% to 2.3%) in the control cohort. No major bleeding event or fatal pulmonary embolism was observed in the patients managed with use of the nomogram. CONCLUSION: This study demonstrated that the administration of warfarin during hospitalization with use of a nomogram designed for the prevention of deep-vein thrombosis following total hip or knee arthroplasty provided effective and safe prophylaxis that was comparable with that provided by physician-adjusted dosing of warfarin.

Anticoagulants↗
PubMed2001

A catalog of prostate cancer nomograms.

PURPOSE: Prediction is central to the management of prostate cancer. Nomograms are devices that make predictions. We organized many nomograms for prostate cancer. MATERIALS AND METHODS: Using MEDLINE a literature search was performed on prostate cancer nomograms from January 1966 to February 2000. We recorded input variables, prediction form, the number of patients used to develop the nomogram and the outcome being predicted. We also recorded the accuracy measures reported by the original authors and whether the nomograms have withstood validation. In addition, we noted whether the nomograms were proprietary or in the public domain. Each nomogram was classified into patient clinical disease state and the outcome being predicted. RESULTS: The literature search generated 42 published nomograms that may be applied to patients in various clinical stages of disease. Of the 42 nomograms only 18 had undergone validation, of which 2 partially failed. Few nomograms have been compared for predictive superiority and none appears to have been compared with clinical judgment alone. CONCLUSIONS: Patients with prostate cancer need accurate predictions. Prognostic nomograms are available for many clinical states and outcomes, and may provide the most accurate predictions currently available. Selection among them and progress in this field are hampered by the lack of comparisons for predictive accuracy.

Biopsy↗
PubMed2003

[The urodynamic nomogram in defining various levels of obstruction in patients with benign prostatic enlargement (part I)].

AIM: To determine matching degrees of urodynamic obstruction among available nomograms in patients with confirmed benign prostatic enlargement (BPE). SAMPLE AND METHODOLOGY: 102 patients with confirmed BPE underwent a complete urodynamic investigation (uroflowmetry, cystometry and pressure/flow study). All the measurements were based on definitions adopted by the International Continence Society. Basic urodynamic data were then manually plotted on the Abrams-Griffiths, URA, ICS and Schafer (LinPURR) nomograms; A/G number was calculated as well. RESULTS: Patients were allocated in the three levels of obstruction by Schafer's nomogram; 24 patients (23.5%) had no obstruction, 28 patients (27.4%) had equivocal or non-defined obstruction, while 50 patients (49.1%) had a significant level of obstruction. Spearman rank correlation coefficient has shown a rather uniform correlation of all nomograms. The correlation between Shafer's nomogram and ICS nomogram is the best one, with rho = 0.89 (p < 0.00001), which is followed by correlations between ICS and A/G nomograms with rho = 0.88 (p < 0.00001) and Schafer and A/G with rho = 0.87 (p < 0.00001). URA nomogram and A/G number have a similar correlation of r = 0.87 (p < 0.00001). According to the levels of obstruction, there is a good correlation in the zone of clear obstruction, as well in the zone out of obstruction among available nomograms (chi 2 test, p > 0.05) (URA has not been subject to this process). However, the above nomograms have shown a significant difference in figures relating to the unclassified zone of obstruction (chi 2 test; p < 0.05). CONCLUSION: Despite a very high degree of correlation among individual nomograms, there are considerable differences in figures relating to the unclassified zone of obstruction. This zone should, therefore, be avoided by establishing an optimum model of clear obstruction defining.

Humans↗