Data Systems in Mental Health

The proper utilization of data information systems in mental health care can noticeably improve the quality and efficacy of such care. The World Health Organization is in a key position to encourage and assist governments in achieving the fullest possible application of knowledge in the development and utilization of such systems to the benefit of the greatest numbers of the world’s population.

This paper briefly delineates some of the common information needs of the providers of mental health care, discusses the feasibility of automated data systems, and describes some already existing psychiatric information systems. Finally, it proposes ways and means by which the WHO can more efficiently aid its member nations by coordinating efforts in establishing mental health information systems. Recommendations include establishment of an information clearinghouse on data systems, a group coordinating dissemination of this information, a common pool of specialists in the area, and development of regional computing facilities under the auspices of the WHO.

Contributions to the theory of optimal resource allocation

A problem in optimal resource allocation is considered for n jobs with identically distributed service times admitting a monotone hazard function. If the hazard function is increasing, it is shown that the procedure of allocating the full resource individually to each job until its completion minimizes the expected completion time of the jth job. The procedure which at any instant of time equally allocated the resource among all of the remaining jobs is shown to minimize the expected total cumulative waiting time if the hazard is decreasing.

Pharmacometabolomic Assessments of Atenolol and Hydrochlorothiazide Treatment Reveal Novel Drug Response Phenotypes

Achieving hypertension (HTN) control and mitigating the adverse health effects associated with HTN continues to be a global challenge. Some individuals respond poorly to current HTN therapies, and mechanisms for response variation remain poorly understood. We used a nontargeted metabolomics approach (gas chromatography time-of-flight/mass spectrometry gas chromatography time-of-flight/mass spectrometry) measuring 489 metabolites to characterize metabolite signatures associated with treatment response to anti-HTN drugs, atenolol (ATEN), and hydrochlorothiazide (HCTZ), in white and black participants with uncomplicated HTN enrolled in the Pharmacogenomic Evaluation of Antihypertensive Responses study. Metabolite profiles were significantly different between races, and metabolite responses associated with home diastolic blood pressure (HDBP) response were identified. Metabolite pathway analyses identified gluconeogenesis, plasmalogen synthesis, and tryptophan metabolism increases in white participants treated with HCTZ (P < 0.05). Furthermore, we developed predictive models from metabolite signatures of HDBP treatment response (P < 1 × 10(-5)). As part of a quantitative systems pharmacology approach, the metabolites identified herein may serve as biomarkers for improving treatment decisions and elucidating mechanisms driving HTN treatment responses.

The natural elimination rate of procalcitonin in patients with normal and impaired renal function

OBJECTIVE

Procalcitonin (PCT) plasma concentrations and its kinetic can be used as a diagnostic tool in critically ill patients and patients with sepsis. Since renal dysfunction is a frequent complication in these patients, and PCT is a protein with a low molecular weight, we have measured the half-life time of PCT after peak concentrations in patients with normal and impaired renal function. We also have analyzed the influence of patients age and gender on PCT elimination kinetics.

DESIGN

Prospective clinical study. Renal dysfunction was assessed by plasma creatinine. The half-life time of PCT was evaluated 24 and 48 h after acute induction of PCT, when the focus of PCT induction has rapidly been eliminated.

SETTING

Intensive care unit of our University hospital, a tertiary health care institution.

PATIENTS

69 patients were included into the study.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

The half-life-time of PCT was not significantly altered during renal dysfunction (26.1-33.1 h, 25-50 percentiles, creatinine clearance < 30 ml/min) when compared with normal renal function (22.3-28.9 h). It neither correlated with creatinine clearance (p=0.14), nor age (p=0.99) or gender (p=0.90, Pearson product-moment correlation).

CONCLUSIONS

The data of the present study demonstrate that assessment of PCT kinetic can also be used for diagnostic and prognostic reasons in patients with renal dysfunction. It may, however, exceed 24 h also in patients with normal renal function. As to the present knowledge, renal secretion does not contribute as a main pathway to PCT elimination.

Der Patient mit Ornithintranscarbamylasemangel

Ornithine transcarbamylase deficiency (OTCD) is the most common inborn urea cycle disorder. Patients with OTCD are at risk of acute metabolic decompensation with hyperammonemia and subsequent encephalopathy, coma and death. Symptoms may be triggered by infections, drugs and stress, evoked by trauma, pain, fear, surgery and anaesthesia or by episodes of protein catabolism, i.e. fasting-induced, post partum or during gastrointestinal bleeding. Several specific considerations must be made for anaesthetic and intensive care management in patients with this disease in order to avoid metabolic decompensation. We report the intensive care management of the first manifestation of late-onset OTCD in a 16-year-old girl and a course of inconspicuous general anaesthesia with midazolam, s-ketamine, fentanyl and isoflurane in a 22-year-old girl with known OTCD.

[Procalcitonin as a marker for severe sepsis in an immunosuppressed patient]

A 22 year old female was admitted to the emergency department with high fever up to 41,5 degrees C, tachycardia, and arterial hypotension. Clinically, she presented with bilateral pulmonary coarse crackles. Diagnosis on admission was pneumonia with septic shock. Intriguingly, procalcitonin (PCT) was increased early, reaching up to 435 ng/mL, while C-reactive protein levels were only moderately increased, with several days delay. The sepsis was originated from a multi-resistant pseudomonas aeruginosa pneumonia. Remarkably, the course of PCT levels reflected the severity of septic shock in that it paralleled noradrenaline demand. Ten months previously, the patient had been diagnosed with acute disseminated brainstem encephalitis (ADEM), and had received two cycles of intravenous cyclophosphamide. Our case illustrates that PCT is an early marker for sepsis and it indicates that PCT may also be a valuable marker for the severity of sepsis in immunosuppressed patients.

Early increase of procalcitonin after cardiovascular surgery in patients with postoperative complications

OBJECTIVE

Type and frequency of postoperative abnormalities were registered after cardiovascular surgery to evaluate the aetiology and diagnostic value of increased concentrations of procalcitonin (PCT) and C-reactive protein (CRP) during the early postoperative period.

DESIGN

Prospective, observational study.

PATIENTS

Two hundred and eight patients undergoing coronary artery bypass grafting or valve replacement requiring cardiopulmonary bypass were monitored for 7 days postoperatively for various types of infectious or non-infectious complications. Plasma PCT and CRP levels were measured on day 1 and day 2 after surgery and, when increased, until day 7.

RESULTS

More patients with PCT above 2 ng/ml on day 1 or 2 (n=55) had postoperative abnormalities (95%) than patients with lower PCT (59%). Specifically, the incidence of three or more criteria of the "systemic inflammatory response syndrome" was 45% versus 4% (area under the curve of the receiver operating characteristic 0.866); positive inotropic support was needed in 65% versus 9% (0.870); respiratory insufficiency (PaO(2)/FIO(2)<200) 38% versus 12% (0.704); proven and suspected bacterial infection 9% versus 1% (0.900) and 24% versus 1% (0.897), respectively. For CRP, the respective areas under the curve were all below 0.63, while all patients had elevated CRP levels, whether they had a complication or not.

CONCLUSIONS

Elevated PCT, but not CRP, correlates with evidence of systemic inflammation and other complications early postoperatively after cardiac surgery. Although the PCT levels do not rise as quickly as the criteria of the systemic inflammatory response syndrome appear, they do reflect systemic inflammation. Early identification and quantification of a systemic inflammatory response may help reduce postoperative complications.

Statistical cost-effectiveness analysis of two treatments based on net health benefits

Statistical methods for cost-effectiveness analysis (CEA) for two treatments that mimic the deterministic optimal rules of CEA are presented. In these rules the objective is to determine the treatment with the maximal effectiveness whose unit cost is less than an amount, lambda, that a decision-maker is willing to pay (WTP). This is accomplished by identifying the treatment with the largest positive net health benefit (NHB), which is a function of lambda, while controlling the familywise error rate both when the WTP value is given and when it is unspecified. Fieller's theorem is used to determine a region of WTP values where the NHBs of the treatments are not distinguishable. For each lambda outside of the confidence region, the larger treatment is identified. A newly developed one-tailed analogue of Fieller's theorem is used to determine the WTP values where a treatment's NHB is positive. The situation in which both treatments are experimental is distinguished from the case where one of the treatments is usual care. The one-tailed confidence region is used in the latter case to obtain the lambda values where the NHBs are not different, and determining the region of positivity of the NHBs may be unnecessary. An example is presented in which the cost-effectiveness of two antipsychotic treatments is evaluated.

Plasma concentrations and clearance of procalcitonin during continuous veno-venous hemofiltration in septic patients

We determined the elimination characteristics of procalcitonin (PCT) during continuous veno-venous hemofiltration (CVVHF) and the resulting effect on PCT plasma levels. A prospective study was conducted in patients with sepsis and acute oliguric renal failure, treated with CVVHF using a polysulfone membrane (Baxter Renaflo II PSHF 1200). Patients had sepsis and PCT plasma levels > 4 ng ml(-1) (n = 26). PCT was measured in the pre- and post-filter plasma and the ultrafiltrate at 0, 5, 10, and 15 min and 1, 2, 4, 6, 12, and 24 h after setup of CVVHF. PCT sieving coefficient was 0.24. Elimination of PCT, however, depended on the duration of filtration, because filter adsorption was the main mechanism of PCT clearance during the first hour of hemofiltration, finally increasing to a clearance of PCT into the ultrafiltrate of 2.8-5.5 mL/min after 2 h. PCT plasma levels were not significantly altered during CVVHF (96% of the initial concentration after 24 h, P = 0.72). Similar to what has been observed with cytokines and other proteins of a comparable molecular weight, PCT is removed from the plasma during CVVHF, but plasma PCT levels are unchanged. Thus, PCT can be used as a diagnostic parameter even in patients with acute renal failure undergoing CVVHF.

[Leukocytopenia as an incidental finding. Finding the etiology]

Any leukopenia of less than 1000/microliter poses an acute threat to life, and mandates an immediate search for the underlying cause. An extensive history-taking (use of drugs? visits abroad? previous illnesses?) and physical examination (splenomegaly? exanthema? signs of hemorrhage?) are mandatory. In addition to a manual differential blood count, bone marrow aspiration for cytological and histological evaluation must be requested. In this overview, the major differential diagnoses, such as allergic agranulocytosis, leukemia, pernicious illnesses (e.g. malaria), hypersplenic syndrome and a number of infectious diseases are discussed.

The plasma elimination rate and urinary secretion of procalcitonin in patients with normal and impaired renal function

BACKGROUND AND OBJECTIVE

The amount of procalcitonin eliminated in the urine and the plasma disappearance rate of procalcitonin were evaluated in patients with normal and impaired renal function, because patients with sepsis are a main target group for procalcitonin measurement, and these patients often develop renal dysfunction.

METHODS

Elimination of procalcitonin in the urine (microgram 12 h-1) was measured in 76 patients. In another 67 patients, the 50% plasma disappearance rate (t1/2, h) was evaluated 48 h after peak concentrations (procalcitonin > 2 micrograms L-1). Renal function was assessed by creatinine clearance.

RESULTS

Procalcitonin elimination in the urine was significantly reduced in patients with severe renal dysfunction. However, the plasma disappearance rate correlated only weakly with renal dysfunction (Spearman's rank correlation R = -0.36, P = 0.004, regression t1/2 = 49.87-0.15 creatinine clearance). The 25% quartile and median were 25.2 h and 30.0 h in patients with normal renal function, and 36.3 h and 44.7 h in patients with severely impaired renal function (creatinine clearance < 30 mL min-1).

CONCLUSIONS

Renal elimination of procalcitonin is not a major mechanism for procalcitonin removal from the plasma. Although the plasma disappearance rate may be prolonged up to 30-50% in some patients with renal dysfunction, clinical diagnostic decisions may not be severely influenced by this moderate prolongation of procalcitonin elimination. We conclude that procalcitonin can be used diagnostically in patients with renal failure as well as in those with normal renal function.

Elimination of procalcitonin and plasma concentrations during continuous veno-venous haemodiafiltration in septic patients

The elimination of procalcitonin and the course of plasma concentrations during continuous veno-venous haemodiafiltration were measured in patients with sepsis or multiple organ dysfunction syndrome, because these patients are a main target group for the measurement of procalcitonin and often require renal replacement therapy. Procalcitonin was measured in the prefilter plasma and the filtrate at 5 min, 15 min and 1, 2, 4, 6, 12, 24 h after set-up of continuous veno-venous haemodiafiltration. In a prospective study, 19 patients with plasma levels of procalcitonin > 3 ng mL-1 and acute oliguric renal failure treated with continuous veno-venous haemodiafiltration using a polysulphone membrane, were evaluated for the study of clearance. Twenty-one control patients (procalcitonin < 2 ng mL-1) were studied to determine whether filtration itself induced a procalcitonin response. No interventions were required. In patients with low procalcitonin concentrations (procalcitonin < 2 ng mL-1) continuous veno-venous haemodiafiltration did not cause a rise in procalcitonin. In patients with increased procalcitonin plasma concentrations (> 3 ng mL-1), the protein was removed through the polysulphone membrane, with a final clearance of 4 mL min-1 after the initial adsorption period (clearance 0.4-0.9 mL min-1 during the first hour of continuous veno-venous haemodiafiltration). Thus, on the average, approximately 10% of plasma concentrations were measurable in the filtrate ultimately. However, procalcitonin plasma levels were not significantly altered during continuous veno-venous haemodiafiltration (86% of the initial concentration after 24 h). Although procalcitonin is removed from the plasma during continuous veno-venous haemodiafiltration in measurable amounts plasma procalcitonin concentrations did not change significantly during haemodiafiltration. Procalcitonin thus can also be used as a diagnostic parameter in patients undergoing continuous veno-venous haemodiafiltration.

Clinical experiences with a new semi-quantitative solid phase immunoassay for rapid measurement of procalcitonin

A self-developing solid-phase immunoassay (B.R.A.H.M.S. PCT-Q, B.R.A.H.M.S.-Diagnostica GmbH, Hennigsdorf, Germany) has recently become available for the semi-quantitative and rapid measurement of procalcitonin (PCT). In this study we examined the validity of this assay at daily clinical routine conditions at five different hospitals in a prospective study. After development of the assay (200 microl plasma, 30 minutes incubation), PCT levels were categorized into four groups (< 0.5 microg/l; > or = 0.5-< 2 microg/l; > or = 2-< 10 microg/l; > or = 10 microg/l) according to the provided reference scale. Samples from patients with suspected elevation of PCT of different etiology (n=237) were read by various analyzers and compared with the results of the Lumitest PCT (B.R.A.H.M.S.-Diagnostica GmbH, Hennigsdorf, Germany). A total of 74.7% of measurements were categorized according to the results of the LumitestPCT, 24.5% were read within the next lower or higher category. Using a +/- 10% range at the reference concentrations (20% at 0.5 microg/l), 82.7% of samples were correctly categorized and 16.4% within the next categories. Using a cut-off value of 2.0 microg/l, 92.0% (94.1% for +/- 10%) of the results were correctly categorized. The semi-quantitative solid phase immunoassay allows a rapid, simple and semi-quantitative measurement of plasma PCT. The validity of the test results and its ease of use are sufficient to support acute diagnostic decisions. However, for the follow-up of PCT concentrations and routine daily measurements, the quantitative luminometric assay should be preferred, when available.

Modulation of the ceramide level, a novel therapeutic concept?

The sphingomyelin (SM) pathway is an ubiquitous and evolutionarily conserved signaling system in which ceramide (CA), generated from SM by the action of various isoforms of sphingomyelinases (SMases) functions as an important second messenger. Recent evidence suggests that branching pathways of sphingolipid metabolism mediate either apoptotic or mitogenic responses depending on cell type and the nature of the stimulus. Events involving SM metabolites and CA in particular include proliferation, differentiation and growth arrest as well as the induction of apoptosis. An improved understanding of SMase-dependent signaling may afford relevant insights into the pathogenesis of diseases and provide novel strategies and selective targets for a therapeutic intervention e.g. in cancer, cardiovascular and neurodegenerative diseases, HIV and septic shock. This article briefly summarizes the role of SMases in signaling pathways, its potential contribution in the development and maintenance of various pathobiological states and analyzes the perspective of a potentially isotype-specifc inhibition of SMases as a novel therapeutic concept.

Influence of pyrrolidine dithiocarbamate on the inflammatory response in macrophages and mouse endotoxin shock

To analyze the immunomodulatory effect of pyrrolidine dithiocarbamate (PDTC) on the endotoxin (LPS) stimulated inflammatory response, we measured the LPS-stimulated cytokine and NO production in murine peritoneal macrophages, J774A.1 cells and human whole blood in the presence of PDTC (60 microM). PDTC significantly inhibited the production of nitrite, IL-1beta and IL-6 in these cells. TNFalpha release was stimulated in murine cells, but suppressed in human whole blood. We further investigated the influence of PDTC on mortality and cytokine release in mouse endotoxin shock. PDTC was i.p. injected 30 min prior to the induction of endotoxin shock in female NMRI-mice and survival was significantly improved as compared to controls (48% vs 20%, n=25 per group). Plasma concentrations of TNFalpha were slightly augmented while IL-6 levels were decreased in PDTC-treated animals as compared to controls, however, without reaching significance. We conclude that PDTC is a potent immunomodulatory substance that modulates the inflammatory response in vitro and reduces mortality in mouse endotoxin shock. The pathophysiological mechanisms of the protective effect of PDTC in vivo, however, appears to be pluripotent, comprising both antioxidative properties and the inhibition of NF-kB.

Power and sample size in cost-effectiveness analysis

For resource allocation under a constrained budget, optimal decision rules for mutually exclusive programs require that the treatment with the highest incremental cost-effectiveness ratio (ICER) below a willingness-to-pay (WTP) criterion be funded. This is equivalent to determining the treatment with the smallest net health cost. The designer of a cost-effectiveness study needs to select a sample size so that the power to reject the null hypothesis, the equality of the net health costs of two treatments, is high. A recently published formula derived under normal distribution theory overstates sample-size requirements. Using net health costs, the authors present simple methods for power analysis based on conventional normal and on nonparametric statistical theory.

Ratio-based and net benefit-based approaches to health care resource allocation: proofs of optimality and equivalence

Both incremental cost-effectiveness ratios and net benefits have been proposed as summary measures for use in cost-effectiveness analyses. We present a unifying proof of the optimality and equivalence of ICER- and net benefit-based approaches to the health resource allocation problem, including both 'fixed budget' and 'fixed price' decision rules. If internally consistent willingness-to-pay values are used, ratio- and net benefit-based decision rules identify the same optimal allocation. Because they have identical resource allocation implications, use of one or other of the two approaches must be based on other criteria, such as their behaviour under conditions of uncertainty.

Postoperative plasma concentrations of procalcitonin after different types of surgery

OBJECTIVE

Procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations were measured after different types of surgery to analyze a possible postoperative induction of procalcitonin (PCT), which might interfere with the diagnosis of bacterial infection or sepsis by PCT.

DESIGN

PCT and CRP plasma levels as well as clinical symptoms of infection were prospectively registered preoperatively and 5 days postoperatively.

SETTING

University hospital, in-patient postoperative care.

PATIENTS

Hundred thirty patients were followed up; 117 patients with a normal postoperative course were statistically analyzed.

INTERVENTIONS

None.

MEASUREMENTS AND RESULTS

PCT concentrations were moderately increased above the normal range in 32 % of patients after minor and aseptic surgery, in 59 % after cardiac and thoracic surgery, and in 95 % of patients after surgery of the intestine. In patients with an abnormal postoperative course, PCT was increased in 12 of 13 patients. CRP was increased in almost all patients.

CONCLUSIONS

Postoperative induction of PCT largely depends on the type of surgery. Intestinal surgery and major operations more often increase PCT, whereas it is normal in the majority of patients after minor and primarily aseptic surgery. PCT can thus be used postoperatively for diagnostic means only when the range of PCT concentrations during the normal course of a certain type of surgery is considered and concentrations are followed up.

Modulation of mouse endotoxin shock by inhibition of phosphatidylcholine-specific phospholipase C

During Gram-negative bacterial infections, lipopolysaccharide (LPS) interacts with monocyte/macrophage receptors, resulting in a host defense response. Activation of intracellular signal transduction pathways implicating various protein kinase and phospholipases is crucial in activating the transcription of genes encoding proinflammatory cytokines and inducible nitric oxide synthase (iNOS). In this article, we demonstrate that in mouse, endotoxin shock activation of phosphatidylcholine-specific phospholipase C (PC-PLC) plays a major role in controlling the inflammatory response. Inhibition of PC-PLC by the specific inhibitor tricyclodecan-9-yl-xanthogenate (D609) before LPS reduced the release of interleukin-1 beta, interleukin-6 and nitric oxide (NO) in vivo. In contrast, tumor necrosis factor-alpha serum levels were not altered by the pretreatment with D609. Consequently, survival from endotoxin shock of D609-treated animals was significantly improved compared with control animals (45% vs. 20%). Thus, inhibition of PC-PLC can reduce the inflammatory response to LPS and may serve as a novel approach to therapy of sepsis.

Classification of the effectiveness of combination treatments

According to FDA regulations, a combination drug is not efficacious unless each component contributes to the claimed effects. For a univariate endpoint, this implies that the combination at specific doses must be superior to each of its components at the same doses. More demanding is the property of synergy, in which the effect of the combination must be superior to the effect expected based on those of its components. If it is equal to those effects, it is additive, and if it is inferior, it is antagonistic. We give regions in the combination dose plane where these concepts are well defined. If the effect of the combination is greater than the greatest effect achievable by any of its components it is therapeutically synergistic. A combination can be antagonistic, yet its components can still contribute to the claimed effects. If it is additive, synergistic or therapeutically synergistic, its components must contribute to the claimed effects. We relate these concepts and provide designs and sequential procedures for determining whether a combination is therapeutically synergistic, synergistic, additive, antagonistic and contributing or antagonistic and non-contributing.

Estimating the size of a population from a single sample: methodology and practical issues

In contrast to classical capture recapture methods, the single-sample method of Laska, Meisner, and Siegel (1988) (LMS) enables estimation of the size of a population, N*, on the basis of a single survey. For example, it may be desired to estimate the unduplicated number of individuals served by a mental health center during the last year on the basis of a 1-week sample. The time since each of the sampled individuals last engaged in the activity that defines the population is ascertained. The LMS estimator of N* and its unbiasedness property are motivated in a simple way, and an improved LMS estimator is introduced if additional information is available. An empirical assessment of the procedure is made using mental health service data for which the true population size is known. The performance of the extended LMS estimator is a substantial improvement over the standard LMS estimator.

The usefulness of average cost-effective ratios

We demonstrate that average cost-effectiveness ratios (CERs) play an important role in the evaluation of the cost-effectiveness of treatments. Criticisms of the usefulness of CERs derive mostly from the context of resource allocation under a constrained budget in which some decisions are based on incremental CERs. However, we show that in many cases, these decision rules are equivalent to decision rules on CERs. This follows for mutually exclusive treatments first, because a treatment is eliminated by extended dominance if and only if there is a mixed treatment with a smaller CER, where the mixing parameter lies in a certain interval. Second, after elimination of treatments by dominance and by extended dominance, resources can be allocated in order of increasing CERs. Moreover, the CER is a parameter that characterizes clinical and economical properties of a treatment independent of its comparators.

Procalcitonin--influence of temperature, storage, anticoagulation and arterial or venous asservation of blood samples on procalcitonin concentrations

In this study we have analysed the influence of temperature and time of storage and of repeated freezing on procalcitonin plasma concentrations ex vivo. We have also analysed the difference of procalcitonin concentrations in arterial or venous blood samples and the influence of different anticoagulation techniques on procalcitonin concentrations (serum, EDTA-, lithium-heparin- or citrate plasma). At room temperature (25 degrees C) a loss of procalcitonin plasma concentrations of 6.4% +/- 2.6% (mean, 2 standard error of the mean) after 3 hours (4.6% +/- 5.2% at 4 degrees C) and 12.3% +/- 3.1% after 24 hours occurred (6.3% +/- 5.0% at 4 degrees C, n = 17 each). Comparing the procalcitonin concentrations of blood samples with different anticoagulants (n = 24 each), there was only a significant difference between procalcitonin concentrations in heparinized plasma and serum (+ 7.6%, difference of the mean). There was no significant influence of the blood sampling technique (arterial or venous line) and of repeated freezing/thawing cycles (up to 3 times) on the procalcitonin concentrations measured. Although the difference of sampling and storage of the blood on procalcitonin concentrations is not significant, multiple factors may act synergistically on the result of procalcitonin measurement. To keep variations of ex vivo conditions as minimal as possible, a standardized technique of anticoagulation, time and temperature of storage is recommended, e.g. the use of EDTA-plasma and storage at room temperature, when samples are measured within 4 hours after blood drawing.

History of violent behaviour and schizophrenia in different cultures. Analyses based on the WHO study on Determinants of Outcome of Severe Mental Disorders

BACKGROUND

Information on patterns and correlates of the violent behaviour of individuals with schizophrenia is largely limited to populations in developed countries. Data from a World Health Organization epidemiological study of schizophrenia and related disorders, the Determinants of Outcome of Severe Mental Disorders (DOSMD), presented an opportunity to study patterns of violence across multinational settings.

METHOD

Centres in 10 countries participated in the DOSMD study. An incidence sample of 1017 patients with schizophrenia who had their first-in-lifetime contact with a helping agency as a result of their psychotic symptoms was obtained. Data were available on their history of violent behaviour, substance use, and demographics.

RESULTS

The occurrence rate of assault in the entire cohort was 20.6 per hundred, but the rate was three times higher in the developing countries (31.5 per hundred) than in developed countries (10.5 per hundred). History of assault was associated with positive symptoms, such as excitement and auditory hallucinations, and with serious alcohol problems.

CONCLUSIONS

The cultural context and the specific characteristics of the disease in individuals with schizophrenia may interactively affect rates of violent behaviour.

Statistical inference for cost-effectiveness ratios

Methods for statistical inference for cost-effectiveness (C/E) ratios for individual treatment and for incremental cost-effectiveness (delta C/ delta E) ratios when two treatments are compared are presented. In a lemma, we relate the relative magnitude of two C/E ratios to the delta C/ delta E ratio. We describe a statistical procedure to test for dominance, or admissibility, that can be used to eliminate an inferior treatment. The one-sided Bonferroni's confidence interval procedure is generalized to the two-sided case. The method requires only that two confidence intervals be available, one for cost and one for effectiveness. We describe Fieller-based confidence intervals and show them to be shorter than Bonferroni intervals. When distribution assumptions hold and variance and covariance estimates are available, Fieller intervals are preferable. However, Bonferroni intervals can be applied in more diverse situations and are easier to calculate. A simple Bonferroni based technique, and a likelihood ratio statistic given by Siegel, Laska and Meisner, for testing the null hypothesis that the C/E ratios of two treatments are equal is presented. The approaches are applied to the data from a phase II clinical trial of a new treatment for sepsis considered previously by others.

Blood volume determination using hydroxyethyl starch: a rapid and simple intravenous injection method

OBJECTIVE

To develop and evaluate a new method for blood volume measurements using hydroxyethyl starch as a dilution marker.

DESIGN

Laboratory and clinical investigation.

SETTING

Neurosurgical operating rooms and anesthesiological laboratories of a university hospital.

PATIENTS

Twelve patients who underwent a neurosurgical operation.

INTERVENTIONS

Anesthesia and operations were carried out by physicians who were not involved in the study. In addition, blood samples were drawn from 50 volunteers.

MEASUREMENTS AND MAIN RESULTS

Blood volume measurements by the hydroxyethyl starch method were validated in vivo by comparison with a conventional carbon monoxide technique. Patients were intravenously injected with hydroxyethyl starch (100 mL) and received simultaneously an injection of carbon monoxide (50 mL) into a closed-circuit ventilation system. Blood samples obtained before and 5 mins after injection were analyzed for carboxyhemoglobin and glucose plasma concentrations after acidic hydrolysis of hydroxyethyl starch. Blood volume was calculated from the difference between glucose concentrations measured after hydrolysis in the plasma, before and after the addition of hydroxyethyl starch. In vitro, the hydroxyethyl starch method had an error and a precision of approximately 2%. In vivo, simultaneous measurements of blood volume using hydroxyethyl starch and carbon monoxide demonstrated a high correlation (r2 = .96, p < .001) between these methods. The mean difference between the two methods relative to their average value was 1.0 +/- 3.5%; the bias was 52.3 mL, and the 95% confidence interval was -64.0 to +168.7 mL.

CONCLUSIONS

Blood volume determination by the hydroxyethyl starch method is accurate and rapid and may enhance perioperative monitoring of fluid and blood therapy.

Statistical methods for cost-effectiveness analyses

A statistical framework is presented for examining cost and effect data on competing interventions obtained from an RCT or from an observational study. Parameters of the join distribution of costs and effects or a regression function linking costs and effects are used to define cost-effectiveness (c-e) measures. Several new c-e measures are proposed that utilize the linkage between costs and effects on the patient level. These measures reflect perspectives that are different from those of the commonly used measures, such as the ratio of expected cost to expected effect, and they can lead to different relative rankings of the interventions. The cost-effectiveness of interventions are assessed statistically in a two stage procedure that first eliminates clearly inferior interventions. Members of the remaining admissible set are then rank ordered according to a c-e preference measure. Statistical techniques, particularly in the multivariate normal case, are given for several commonly used c-e measures. These techniques provide methods for obtaining confidence intervals, for testing the hypothesis of admissibility and for the equality of interventions, and for ranking interventions. The ideas are illustrated for a hypothetical clinical trial of antipsychotic agents for community-based persons with mental illness.

Estimating population size when duplicates are present

Each of K mental health programmes reports the number of patients served in a year. The sum of these numbers, y, is an overcount because some patients are seen in more than one programme. Health care planners need to know the unduplicated number served by the mental health system. Thus, there is an unknown number, M, of distinct individuals who appear on one or more of K lists; some appear on multiple lists and the duplicates are not readily identifiable. Let X be the number of lists on which a randomly selected individual appears. When E(X) is known, y/E(X) is the natural estimator of M. We assume that we know the number of programmes, Xi, used by the ith individual in a random sample of recipients of service. Here, the intuitive estimator, Y/X has desirable statistical properties. We give confidence interval estimators for M. We apply the method to estimate the number of individuals served in 1991 by the mental health programmes in New York State.

Placebo washout in trials of antipsychotic drugs

For antipsychotic phase 3 clinical trials, we compare the relative merits of a placebo washout period with an alternate design strategy using a low-dose antipsychotic treatment. Evaluations are made with respect to the achievement of specific clinical trial design goals including the effect on power for detecting between-treatment and within-treatment pre-post differences. The relative merits of these two designs are discussed separately for those patients who enter the initial leadin period after withdrawal from previous antipsychotic medication and for those not on medication immediately before that period.

Plasma haloperidol levels and clinical effects in schizophrenia and schizoaffective disorder

BACKGROUND

Plasma haloperidol levels between 5 and 11 ng/mL may be clinically optimal for acutely exacerbated schizophrenia, but the evidence for this therapeutic window has been inconsistent.

METHODS

Haloperidol was administered in a double-blind manner during two consecutive 3-week experimental periods to 65 patients with acutely exacerbated schizophrenia or schizoaffective disorder. Two plasma levels were targeted: "low" (2 ng/mL) and "moderate" (10 ng/mL). The subjects were randomly assigned to four treatment sequences (low-low, low-moderate, moderate-moderate, or moderate-low).

RESULTS

In the first 3 weeks, the antipsychotic efficacy of haloperidol increased with plasma levels up to approximately 12 ng/mL. In the second 3 weeks, decrease of plasma levels reduced negative symptoms.

CONCLUSION

For most patients, plasma levels not exceeding 12 ng/mL yield the best results in the first 3 weeks of treatment. Subsequent lowering of the plasma levels may improve negative symptoms.

Induction of nitric oxide synthase activity in phagocytic cells inhibited by tricyclodecan-9-yl-xanthogenate (D609)

1. The synthesis of nitric oxide (NO) by immune-stimulated murine phagocytic cells (J774) and the modulation of this synthesis by tricyclodecan-9-yl-xanthogenate (D609), a specific inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), was investigated. D609 dose-dependently suppressed production of NO, as measured by the release of nitrite and nitrate, in response to lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) in intact cultured cells with an IC50 of approximately 20 micrograms ml-1. D609 at 40 micrograms ml-1 completely abrogated immune-stimulated nitrite production. 2. The inhibitory effects of D609 on nitrite production were time-dependent and restricted to the first 18 h post-stimulation. D609 did not inhibit nitrite production in the cytosol of immune-stimulated phagocytes. 3. These findings indicate that the xanthogenate, D609, is a potent inhibitor of the induction of NO-synthase activity in immune-stimulated phagocytes. Furthermore, since D609 has been demonstrated to inhibit PC-PLC specifically, our findings suggest that the activation of this enzyme by LPS and IFN-gamma is a proximal step in the signal transduction of inducible NO-synthase in phagocytic cells.

Simple designs and model-free tests for synergy

Current statistical designs for studying whether two or more agents in combination act synergistically nearly always require the study of several doses of many dose ratios. The analysis is usually based on an assumed parametric model of the dose-response surface. In this paper, for both quantal and quantitative response variables, sufficient conditions are given for establishing synergy at a dose of the combination without the need to specify the model. This enables the use of simple designs with few doses even when there is sparse knowledge of the dose-response curves of the individual agents. The Min test, used for testing whether an identified treatment is best, may be used for testing synergy. Power issues are discussed.

A plant-capture method for estimating the size of a population from a single sample

To estimate the size of a population a plant-capture method, an alternative to the classic capture-mark-recapture model, is presented. Known or marked individuals otherwise indistinguishable from the remainder of the population are planted followed by an effort to capture members from the augmented population. Maximum likelihood estimators and a confidence region together with the expected length of the confidence interval for the size of the population as a function of the number of plants are given. A methodology for comparing the cost efficiency of plant-capture to capture-recapture is developed. An application to counting the homeless is given.

Haloperidol blood levels and clinical effects

This study explored the relationships between plasma levels and the clinical effects of haloperidol in 176 acutely exacerbated schizophrenic or schizoaffective patients. After a single-blind placebo period of 1 week (period 1), they entered the double-blind period 2 randomly assigned to one of three plasma levels of haloperidol: low (2 to 13 ng/mL), medium (13.1 to 24 ng/mL), or high (24.1 to 35 ng/mL). Patients whose conditions did not improve in period 2 continued on one of the three haloperidol levels (period 3). Periods 2 and 3 lasted 6 weeks each. Only minor differences in clinical responses were noted among the three levels of haloperidol. These results imply that low or moderate doses of neuroleptics are appropriate for many acutely psychotic patients.

A risk-based prospective payment system that integrates patient, hospital and national costs

We suggest that a desirable form for prospective payment for inpatient care is hospital average cost plus a linear combination of individual patient and national average cost. When the coefficients are chosen to minimize mean squared error loss between payment and costs, the payment has efficiency and access incentives. The coefficient multiplying patient costs is a hospital specific measure of financial risk of the patient. Access is promoted since providers receive higher reimbursements for risky, high cost patients. Historical cost data can be used to obtain estimates of payment parameters. The method is applied to Medicare data on psychiatric inpatients.

Control for environmental risk factors in assessing genetic effects on disease familial aggregation

A probabilistic model was developed to assess the impact of two independent dichotomous familial risk factors on familial aggregation of a disorder in pairs of relatives where one member was ascertained as a proband or index subject (i.e., a case or control). Under this model, one risk factor is of primary interest (i.e., a susceptibility gene), while the effect of the other is to be controlled (i.e., an environmental risk factor). Familial aggregation was examined within strata defined by the status of proband and relative with respect to the environmental factor. The findings suggest that for proband-relative pairs, under both the additive and multiplicative models, an environmental factor can be controlled in the analysis based solely on the status of the proband. If the relation between the genetic and environmental factors is neither additive nor multiplicative, however, the analysis must take account of environmental risk factors in both proband and relative.

Predicting assaultiveness in psychiatric inpatients: a pilot study

A sample of 87 psychiatric inpatients known to have been assaultive while in the hospital was contrasted with a matched group of nonviolent patients to identify the personal risk factors that distinguished the two groups. Data were collected using a personal history interview, a neurological examination, and an electroencephalogram. The four risk factors identified--neurological abnormality, history of violent crime, history of violent suicide attempts, and deviant family environment in childhood--were used to develop a statistical model predicting which subjects in a sample of newly admitted patients would become assaultive during the first three months after admission. The predicted classification of patients was found to be significantly related to subsequent assaultive behavior.

An analytic approach to quantifying pain scores

Statistical problems in clinical trials frequently involve fitting regression lines when the underlying data are categorical or ordinal response variables. Usually an ad hoc a priori quantification is used to assign values to these ordinal responses. For pain intensity data collected in analgesic trials, the usual approach is to set none equal to 0, mild equal to 1, moderate equal to 2, and severe equal to 3. While this scheme has been generally accepted, on the basis that for similar clinical trials reasonably similar results are obtained by different investigators, concern exists that the distances between pain scores are probably not equal. A method is presented for quantifying categorical responses so that the resulting scores maximize the simultaneous fit of the dose-response regression lines. The optimal scores derived by this technique may then be used in a bioassay analysis to estimate the relative potency of 2 compounds. As illustrative examples, this method was applied to data from 2 clinical trials and the results were compared to the usual method.

Combining multivariate bioassays

Linear multivariate theory is applied to the problem of combining several multivariate bioassays. Results are an asymptotic test of the hypothesis of a common log relative potency; the maximum likelihood estimator of the common log relative potency; and an exact and asymptotic confidence interval estimator for log relative potency.

Optimal crossover designs in the presence of carryover effects

Under either the random patient-effect model with sequence effects or the fixed patient-effect model, the usual two-period, two-treatment crossover design, AB,BA, cannot be used to estimate the contrast between direct treatment effects when unequal carryover effects are present. If baseline observations are available, the design AB,BA can validly be used to estimate a treatment contrast. However, the design AB,BA,AA,BB with baseline observations is more efficient. In fact, we show that this design is optimal whether or not baseline observations are available. For experiments with more than two periods, universally optimal designs are found for both models, with and without carryover effects. It is shown that uncertainty about the presence of carryover effects is of little or no consequence, and the addition of baseline observations is of little or no added value for designs with three or more periods; however, if the experiment is limited to only two periods the investigator pays a heavy penalty.

Matched-pairs study of reserpine use and breast cancer

This paper reports on an analysis of psychiatric population. 55 female patients with breast cancer were matched with non-cancer patients on age, year of admission, psychiatric diagnosis, race, and religion. Reserpine use was examined for yearly use by each year preceding the diagnosis of breast cancer, by cumulative yearly use, and by other defined time periods. Regardless of the definition of reserpine user, there were no significant increased relative risks of breast cancer for those women on reserpine. There was a fairly low proportion of patients from each group who were on the drug in any given year, and a fairly wide range of total dosage received. Over half of the women used reserpine at some time during their hospital stay.