Phase 2 Trial of Ibudilast in Progressive Multiple Sclerosis.

BACKGROUND: There are limited treatments for progressive multiple sclerosis. Ibudilast inhibits several cyclic nucleotide phosphodiesterases, macrophage migration inhibitory factor, and toll-like receptor 4 and can cross the blood-brain barrier, with potential salutary effects in progressive multiple sclerosis. METHODS: We enrolled patients with primary or secondary progressive multiple sclerosis in a phase 2 randomized trial of oral ibudilast (≤100 mg daily) or placebo for 96 weeks. The primary efficacy end point was the rate of brain atrophy, as measured by the brain parenchymal fraction (brain size relative to the volume of the outer surface contour of the brain). Major secondary end points included the change in the pyramidal tracts on diffusion tensor imaging, the magnetization transfer ratio in normal-appearing brain tissue, the thickness of the retinal nerve-fiber layer, and cortical atrophy, all measures of tissue damage in multiple sclerosis. RESULTS: Of 255 patients who underwent randomization, 129 were assigned to ibudilast and 126 to placebo. A total of 53% of the patients in the ibudilast group and 52% of those in the placebo group had primary progressive disease; the others had secondary progressive disease. The rate of change in the brain parenchymal fraction was -0.0010 per year with ibudilast and -0.0019 per year with placebo (difference, 0.0009; 95% confidence interval, 0.00004 to 0.0017; P=0.04), which represents approximately 2.5 ml less brain-tissue loss with ibudilast over a period of 96 weeks. Adverse events with ibudilast included gastrointestinal symptoms, headache, and depression. CONCLUSIONS: In a phase 2 trial involving patients with progressive multiple sclerosis, ibudilast was associated with slower progression of brain atrophy than placebo but was associated with higher rates of gastrointestinal side effects, headache, and depression. (Funded by the National Institute of Neurological Disorders and Stroke and others; NN102/SPRINT-MS ClinicalTrials.gov number, NCT01982942 .).

Constructing an adaptive care model for the management of disease-related symptoms throughout the course of multiple sclerosis--performance improvement CME.

BACKGROUND: Symptom management remains a challenging clinical aspect of MS. OBJECTIVE: To design a performance improvement continuing medical education (PI CME) activity for better clinical management of multiple sclerosis (MS)-related depression, fatigue, mobility impairment/falls, and spasticity. METHODS: Ten volunteer MS centers participated in a three-stage PI CME model: A) baseline assessment; B) practice improvement CME intervention; C) reassessment. Expert faculty developed performance measures and activity intervention tools. Designated MS center champions reviewed patient charts and entered data into an online database. Stage C data were collected eight weeks after implementation of the intervention and compared with Stage A baseline data to measure change in performance. RESULTS: Aggregate data from the 10 participating MS centers (405 patient charts) revealed performance improvements in the assessment of all four MS-related symptoms. Statistically significant improvements were found in the documented assessment of mobility impairment/falls (p=0.003) and spasticity (p<0.001). For documentation of care plans, statistically significant improvements were reported for fatigue (p=0.007) and mobility impairment/falls (p=0.040); non-significant changes were noted for depression and spasticity. CONCLUSIONS: Our PI CME interventions demonstrated performance improvement in the management of MS-related symptoms. This PI CME model (available at www.achlpicme.org/ms/toolkit) offers a new perspective on enhancing symptom management in patients with MS.

Therapy optimization in multiple sclerosis: a prospective observational study of therapy compliance and outcomes.

BACKGROUND: Data sources for MS research are numerous but rarely provide an objective measure of drug therapy compliance coupled with patient-reported health outcomes. The objective of this paper is to describe the methods and baseline characteristics of the Therapy Optimization in MS (TOP MS) study designed to investigate the relationship between disease-modifying therapy compliance and health outcomes. METHODS: TOP MS was designed as a prospective, observational, nationwide patient-focused study using an internet portal for data entry. The protocol was reviewed and approved by Sterling IRB. The study was registered with ClinicalTrials.gov. It captured structured survey data monthly from MS patients recruited by specialty pharmacies. Data collection included the clinical characteristics of MS such as MS relapses. Disability, quality of life and work productivity and activity impairment were assessed quarterly with well-validated scales. When events like severe fatigue or new or worsening depression were reported, feedback was provided to treating physicians. The therapy compliance measure was derived from pharmacy drug shipment records uploaded to the study database. The data presented in this paper use descriptive statistics. RESULTS: The TOP MS Study enrolled 2966 participants receiving their disease-modifying therapy (DMT) from specialty pharmacies. The mean age of the sample was 49 years, 80.4% were female, 89.9% were Caucasian and 55.7% were employed full or part time. Mean time since first symptoms was 11.5 years; mean duration since diagnosis was 9.5 years. Patient-reported EDSS was 3.5; 72.2% had a relapsing-remitting disease course. The most commonly reported symptoms at the time of enrollment were fatigue (74.7%), impaired coordination or balance (61.8%) and numbness and tingling (61.2%). Half of the sample was using glatiramer acetate and half was using beta-interferons. CONCLUSION: Demographic and clinical characteristics of the TOP MS sample at enrollment are consistent with other community-based MS samples, and the sample appears to be representative of DMT users in the US. TOP MS data can be used to explore the associations between disease-modifying therapy compliance and health outcomes. TRIAL REGISTRATION: ClinicalTrials.gov (NCT00819000).

Sphingosine 1-phosphate receptor modulators in multiple sclerosis treatment: A practical review.

Four sphingosine 1-phosphate (S1P) receptor modulators (fingolimod, ozanimod, ponesimod, and siponimod) are approved by the US Food and Drug Administration for the treatment of multiple sclerosis. This review summarizes efficacy and safety data on these S1P receptor modulators, with an emphasis on similarities and differences. Efficacy data from the pivotal clinical trials are generally similar for the four agents. However, because no head-to-head clinical studies were conducted, direct efficacy comparisons cannot be made. Based on the adverse event profile of S1P receptor modulators, continued and regular monitoring of patients during treatment will be instructive. Notably, the authors recommend paying attention to the cardiac monitoring guidelines for these drugs, and when indicated screening for macular edema and cutaneous malignancies before starting treatment. To obtain the best outcome, clinicians should choose the drug based on disease type, history, and concomitant medications for each patient. Real-world data should help to determine whether there are meaningful differences in efficacy or side effects between these agents.

Opportunistic infections of the central nervous system in the transplant patient.

Therapeutic advances in transplantation medicine have resulted in ever expanding patient populations that receive organ or stem cell transplantation. Modern potent immunomodulatory therapies have resulted in improvements in allograft and patient survival, but, consequently, as a result of the immunosuppressive state, transplant recipients are highly vulnerable to infection, including those that affect the central nervous system (CNS). CNS infections present a diagnostic and therapeutic challenge for clinicians involved in the care of the transplant patient, with a propensity to result in profound morbidity and often high mortality in this patient population. Here, we review major opportunistic pathogens of the CNS seen in transplant patients, highlighting distinguishing epidemiologic and clinical features.

Differential Diagnosis of Tumor-like Brain Lesions.

Purpose of Review: Tumor-like brain lesions are rare and commonly suggest a neoplastic etiology. Failure to rapidly identify non-neoplastic causes can lead to increased morbidity and mortality. In this review, we describe 10 patients who presented with atypical, non-neoplastic tumor-like brain lesions in which brain biopsy was essential for a correct diagnosis and treatment. Recent Findings: There has been increasing recognition of autoimmune conditions affecting the nervous system, and many of those diseases can cause tumor-like brain lesions. Currently available reports of non-neoplastic tumor-like brain lesions are scarce. Most case series focus on tumefactive demyelinating lesions, and a comprehensive review including other neuroimmunological conditions such as CNS vasculitis, neurosarcoidosis, histiocytic and infectious etiologies is lacking. Summary: We review the literature on tumor-like brain lesions intending to increase the awareness and differential diagnosis of non-neoplastic brain tumor mimics. We advocate for earlier brain biopsies, which, in our case series, significantly changed diagnosis, management, and outcomes.

Autologous Hematopoietic Stem Cell Transplant in Multiple Sclerosis: Recommendations of the National Multiple Sclerosis Society.

Importance: Autologous hematopoietic stem cell transplant (AHSCT) for multiple sclerosis has gained increasing interest in recent years. Despite the availability of many US Food and Drug Administration-approved disease-modifying therapies, some patients do not respond adequately and others may have very early aggressive disease that prompts consideration of alternative, highly effective, long-lasting therapy. The National Medical Advisory Committee of the National Multiple Sclerosis Society has reviewed recent literature on AHSCT for the purpose of making recommendations about its use based on current knowledge, as well as pointing out areas of controversy and issues requiring further research. Observations: Studies on AHSCT have repeatedly demonstrated high efficacy and a durable outcome in people with relapsing multiple sclerosis. Recent studies have shown considerable improvement in the safety of the procedure, with much lower mortality rates than were reported earlier. Consensus is emerging about the characteristics of the best candidates for the procedure. Questions remain about the ideal protocol, particularly about the best conditioning regimen to be used to kill immune cells. Larger randomized clinical trials are needed to address the question of whether AHSCT has advantages over the most efficacious disease-modifying agents currently available. One such trial (Best Available Therapy Versus Autologous Hematopoietic Stem Cell Transplant for Multiple Sclerosis [BEAT-MS) is currently in progress. Conclusions and Relevance: The National Multiple Sclerosis Society believes that AHSCT may be a useful treatment option for people with relapsing multiple sclerosis who demonstrate substantial breakthrough disease activity (ie, new inflammatory central nervous system lesions and/or clinical relapses) despite treatment with high-efficacy disease-modifying therapy or have contraindications to high-efficacy disease-modifying therapies. The best candidates are likely people younger than 50 years with shorter durations of disease (<10 years). The procedure should only be performed at centers with substantial experience and expertise. Ideally, recipients of the procedure should be entered into a single database, and further research is needed to establish ideal cell mobilization and immune-conditioning regimens.

Clinical and MRI efficacy of sc IFN ß-1a tiw in patients with relapsing MS appearing to transition to secondary progressive MS: post hoc analyses of PRISMS and SPECTRIMS.

This study evaluated efficacy of subcutaneous (sc) interferon beta-1a (IFN ß-1a) 44 µg 3 × weekly (tiw) in patients appearing to transition from relapsing-remitting multiple sclerosis (RRMS) to secondary progressive MS (SPMS). The PRISMS study included 560 patients with RRMS (EDSS 0-5.0; ≥ 2 relapses in previous 2 years), and the SPECTRIMS study included 618 patients with SPMS (EDSS 3.0-6.5 and ≥ 1-point increase in previous 2 years [≥ 0.5 point if 6.0-6.5]) randomly assigned to sc IFN ß-1a 44 or 22 µg or placebo for 2-3 years, respectively. These post hoc analyses examined five subgroups of MS patients with EDSS 4.0-6.0: PRISMS (n = 59), PRISMS/SPECTRIMS (n = 335), PRISMS/SPECTRIMS with baseline disease activity (n = 195; patients with either ≥ 1 relapse within 2 years before baseline or ≥ 1 gadolinium-enhancing lesion at baseline), PRISMS/SPECTRIMS without baseline disease activity (n = 140), and PRISMS/SPECTRIMS with disease activity during the study (n = 202). In the PRISMS and PRISMS/SPECTRIMS subgroups, sc IFN ß-1a delayed disability progression, although no significant effect was observed in PRISMS/SPECTRIMS subgroups with activity at baseline or activity during the study (regardless of baseline activity). In the PRISMS/SPECTRIMS subgroup, over year 1 (0-1) and 2 (0-2), sc IFN ß-1a 44 µg tiw significantly reduced annualized relapse rate (p ≤ 0.001), and relapse risk (p < 0.05) versus placebo. Similar results were seen for the PRISMS/SPECTRIMS with baseline disease activity subgroup. Subcutaneous IFN ß-1a reduced T2 burden of disease and active T2 lesions in the PRISMS/SPECTRIMS subgroups overall, with and without baseline activity. In conclusion, these post hoc analyses indicate that effects of sc IFN ß-1a 44 µg tiw on clinical/MRI endpoints are preserved in a patient subgroup appearing to transition between RRMS and SPMS.

Serum matrix metalloproteinase levels correlate with brain injury in human immunodeficiency virus infection.

Circulating levels of specific matrix metalloproteinases (MMPs; 1 and 7) were evaluated as correlates of brain injury in eight individuals in advanced human immunodeficiency virus (HIV) infection. Neurological status was quantified in vivo with automated segmentation algorithms and with diffusion tensor imaging. Both metalloproteinases correlated with microstructural brain alterations and the degree of atrophy. MMPs may influence neurological outcome through involvement in neuroimmune response, blood-brain barrier permeability, leukocyte migration, and MMP-mediated neurotoxicity.

The implications of immunogenicity for protein-based multiple sclerosis therapies.

Administered proteins are inherently immunogenic, which may influence their efficacy or safety when used therapeutically. A review of the published literature was performed to compare and evaluate the development and consequences of antibodies against therapeutic protein agents for the treatment of multiple sclerosis (MS). Interferon beta (IFNbeta), glatiramer acetate (GA), and natalizumab are all protein-based therapeutic agents approved to treat MS and are associated with the development of antibodies. Both binding antibodies and neutralizing antibodies (NAbs) develop to varying degrees in patients treated with any of the formulations of IFNbeta. Comparison between studies is complicated by differences in methods, assays, criteria for determining NAb positivity, treatment duration, and fluctuation of NAb status. Despite these confounding factors, current data indicate that high-titer persistent NAbs may be relevant in terms of their effect on IFNbeta bioavailability and bioefficacy. GA-reactive antibodies developed in a high proportion of GA-treated patients, but the clinical relevance of these antibodies remains to be established. Immunogenicity against natalizumab was associated with reduced efficacy and increased incidence of infusion reactions. Other emerging monoclonal antibody therapeutics have also been associated with the development of antibodies. Experience with generic biosimilars of other protein therapeutics suggests that the immunogenicity of generic biosimilar agents cannot be assumed and must be established for each formulation.

Acute Exertional Upper-Extremity Rhabdomyolysis as a Result of a Single Training Event: Report of 3 Female Trainees.

Early diagnosis and comprehensive management of exertional rhabdomyolysis are crucial to ensure full recovery and avoidance of complications.

Cladribine tablets added to IFN-ß in active relapsing MS: The ONWARD study.

OBJECTIVE: To evaluate the safety and efficacy of cladribine tablets in patients still experiencing active relapsing MS despite interferon (IFN)-ß treatment. METHODS: A 96-week phase II study, randomizing patients treated with IFN-ß to cladribine tablets 3.5 mg/kg/IFN-ß or placebo/IFN-ß. Patients were to receive cladribine tablets 3.5 mg/kg/IFN-ß or placebo/IFN-ß in a 2:1 ratio (n = 172) with safety and exploratory efficacy outcomes being assessed. RESULTS: Adverse events (AEs) and serious AEs were similar across treatment groups, except lymphopenia. Fifty of 124 (40.3%) cladribine/IFN-ß recipients vs 0% of placebo/IFN-ß recipients reported lymphopenia as an AE, with grade 3/4 lymphopenia (laboratory lymphocyte count < 500 cells/mm3) experienced by 79/124 (63.7%) vs 1 (2.1%), respectively. Patients treated with cladribine tablets 3.5 mg/kg/IFN-ß were 63% less likely to have a qualifying relapse than placebo/IFN-ß recipients, and cladribine tablets 3.5 mg/kg/IFN-ß reduced most MRI measures of disease activity. CONCLUSIONS: In patients with active relapsing MS despite IFN-ß treatment, cladribine tablets 3.5 mg/kg/IFN-ß reduced relapses and MRI lesion activity over 96 weeks compared with placebo/IFN-ß but led to an increased incidence of lymphopenia. CLASSIFICATION OF EVIDENCE: This study provides Class I evidence that for patients with active relapsing MS despite IFN-ß treatment, cladribine tablets added to IFN-ß reduced relapses and MRI lesion activity over 96 weeks and increased the incidence of lymphopenia. CLINICAL TRIAL REGISTRATION: NCT00436826.

Platelet decline: an avenue for investigation into the pathogenesis of human immunodeficiency virus -associated dementia.

BACKGROUND: The identification of biomarkers identifying onset of human immunodeficiency virus-associated dementia (HIV-D) is critical for diagnosis and the elucidation of pathophysiologic pathways. OBJECTIVE: To examine the association between platelet decline from baseline and HIV-D. DESIGN: Prospective cohort study within the North-East AIDS Dementia cohort. SETTING: Four participating referral centers in the United States. PARTICIPANTS: A total of 396 subjects with advanced human immunodeficiency virus (HIV) infection recruited between 1998 and 2003 and undergoing serial neurologic assessments. Eligibility criteria required CD4 cell counts less than 200/microL or less than 300/microL with evidence of cognitive impairment. A cohort subset without prevalent HIV-D at baseline and without incident HIV-D at the visit immediately after baseline was analyzed (n = 146). Main Outcome Measure Time to first diagnosis of HIV-D. RESULTS: After a median follow-up of 31.1 months, 40 subjects developed HIV-D. Platelet decline from baseline was associated with the development of HIV-D when examined as a time-dependent variable lagged by 6 to 12 months before outcome (multivariate hazard ratio [HR], 2.39; 95% confidence interval [CI], 1.14-5.02; P = .02). This association was stronger during the first 2 years of follow-up (multivariate HR, 6.76; 95% CI, 2.36-19.41; P < .001) than during later years (multivariate HR, 0.94; 95% CI, 0.33-2.67; P = .90). CONCLUSIONS: These results suggest that individuals with declining platelet counts are at greater risk for HIV-D and that the dynamics of circulating platelets vary with respect to the temporal progression of HIV-D. This highlights an avenue to be explored in the understanding of HIV-D pathogenesis.

Robot-guided ankle sensorimotor rehabilitation of patients with multiple sclerosis.

BACKGROUND: People with multiple sclerosis (MS) often develop symptoms including muscle weakness, spasticity, imbalance, and sensory loss in the lower limbs, especially at the ankle, which result in impaired balance and locomotion and increased risk of falls. Rehabilitation strategies that improve ankle function may improve mobility and safety of ambulation in patients with MS. This pilot study investigated effectiveness of a robot-guided ankle passive-active movement training in reducing motor and sensory impairments and improving balance and gait functions. METHODS: Seven patients with MS participated in combined passive stretching and active movement training using an ankle rehabilitation robot. Six of the patients finished robotic training 3 sessions per week over 6 weeks for a total of 18 sessions. Biomechanical and clinical outcome evaluations were done before and after the 6-week treatment, and at a follow-up six weeks afterwards. RESULTS: After six-week ankle sensorimotor training, there were increases in active range of motion in dorsiflexion, dorsiflexor and plantar flexor muscle strength, and balance and locomotion (p<0.05). Proprioception acuity showed a trend of improvement. Improvements in four biomechanical outcome measures and two of the clinical outcome measures were maintained at the 6-week follow-up. The study showed the six-week training duration was appropriate to see improvement of range of motion and strength for MS patients with ankle impairment. CONCLUSION: Robot-guided ankle training is potentially a useful therapeutic intervention to improve mobility in patients with MS.

Demonstration of equivalence of a generic glatiramer acetate (Glatopa™).

Glatiramer acetate (GA) has been available under the brand name Copaxone® for nearly two decades. Recently, the US Food and Drug Administration (FDA) approved the first generic GA, Glatopa™, as fully substitutable for all indications for which Copaxone 20mg is approved; Glatopa also represents the first FDA-approved "AP-rated," substitutable generic for treating patients with MS. Glatiramer acetate is a complex mixture of polypeptides and, consequently, its characterization presented challenges not generally encountered in drug development. Despite its complexity, and without requiring any clinical data, approval was accomplished through an Abbreviated New Drug Application in which equivalence to Copaxone was evaluated across four criteria: starting materials and basic chemistry; structural signatures for polymerization, depolymerization, and purification; physicochemical properties; and biological and immunological properties. This article describes the rigorous overall scientific approach used to successfully establish equivalence between Glatopa and Copaxone, and presents key representative data from several of the comprehensive sets of physicochemical (structural) and biological (functional) assays that were conducted.

Diagnostic utility of aquaporin-4 in the analysis of active demyelinating lesions.

OBJECTIVE: To assess, in a surgical biopsy cohort of active demyelinating lesions, the diagnostic utility of aquaporin-4 (AQP4) immunohistochemistry in identifying neuromyelitis optica (NMO) or NMO spectrum disorder (NMOSD) and describe pathologic features that should prompt AQP4 immunohistochemical analysis and AQP4-immunoglobulin G (IgG) serologic testing. METHODS: This was a neuropathologic cohort study of 20 surgical biopsies (19 patients; 11 cord/9 brain), performed because of diagnostic uncertainty, interpreted as active demyelinating disease and containing 2 or more of the following additional features: tissue vacuolation, granulocytic infiltrates, or astrocyte injury. RESULTS: AQP4 immunoreactivity was lost in 18 biopsies and increased in 2. Immunopathologic features of the AQP4 loss cohort were myelin vacuolation (18), dystrophic astrocytes and granulocytes (17), vascular hyalinization (16), macrophages containing glial fibrillary acid protein (GFAP)-positive debris (14), and Creutzfeldt-Peters cells (0). All 14 cases with available serum tested positive for AQP4-IgG after biopsy. Diagnosis at last follow-up was NMO/NMOSD (15) and longitudinally extensive transverse myelitis (1 each relapsing and single). Immunopathologic features of the AQP4 increased cohort were macrophages containing GFAP-positive debris and granulocytes (2), myelin vacuolation (1), dystrophic astrocytes (1), Creutzfeldt-Peters cells (1), and vascular hyalinization (1). Diagnosis at last follow-up was multiple sclerosis (MS) and both tested AQP4-IgG seronegative after biopsy. CONCLUSIONS: AQP4 immunohistochemistry with subsequent AQP4-IgG testing has diagnostic utility in identifying cases of NMO/NMOSD. This study highlights the importance of considering NMOSD in the differential diagnosis of tumefactive brain or spinal cord lesions. AQP4-IgG testing may avert biopsy and avoid ineffective therapies if these patients are erroneously treated for MS.

A pilot study of cidofovir for progressive multifocal leukoencephalopathy in AIDS.

OBJECTIVE: To assess the safety, tolerability and effect of cidofovir for HIV-1 associated progressive multifocal leukoencephalopathy. DESIGN: Prospective, open-label study in nine AIDS Clinical Trials Units. PATIENTS AND METHODS: Twenty-four HIV-1-infected individuals, with neuroimaging and clinical findings consistent with PML, and symptoms for 90 days or less, whose diagnosis was confirmed by the detection of JC virus DNA in the cerebrospinal fluid or brain biopsy, received cidofovir 5 mg/kg intravenously at baseline and 1 week, followed by infusions every 2 weeks with the dose adjusted for renal function. Follow-up continued to 24 weeks. The safety of cidofovir and changes in neurological examination scores between baseline and week 8 were assessed. RESULTS: Seventeen subjects were receiving potent antiretroviral agents. Survival at 12 weeks was 54%. The CD4 cell count at entry was significantly associated with survival (P = 0.02). Five subjects discontinued treatment because of toxicity: a 50% or greater decrease in intraocular pressure in either eye in four, and proteinuria in one. Overall, magnetic resonance imaging abnormalities and neurological examination scores worsened. Only two subjects experienced a 25% or greater improvement in neurological examination scores at week 8, which were significantly better in subjects with HIV-1-RNA levels of 500 copies/ml or less at entry compared with those with HIV-1-RNA levels over 500 copies/ml (P = 0.05). CONCLUSION: Cidofovir did not improve neurological examination scores at week 8. However, such scores were significantly better in subjects who entered with suppressed plasma HIV-1-RNA levels, which could be the result of control of HIV-1 infection itself or cidofovir.

Whole brain diffusion tensor imaging in HIV-associated cognitive impairment.

BACKGROUND AND PURPOSE: Quantitative MR imaging strategies may have considerable potential for in vivo assessment of neuropathologic changes associated with HIV. This investigation evaluated the prognostic significance of whole brain histogram-derived diffusion tensor imaging indices with respect to severity of cognitive impairment and measures of clinical status in cases of HIV. METHODS: Quantitative indices derived with diffusion tensor imaging, including whole brain fractional anisotropy and the apparent diffusion coefficient, were compared for six patients with HIV and eight control volunteers. Relationships between whole brain indices and specific measures of dementia severity and clinical status were examined. RESULTS: Whole brain fractional anisotropy was reduced in patients with HIV and was significantly associated with severity of dementia, as indicated by several widely used clinical and functional status measures. Summary fractional anisotropy measures were more prognostic of dementia status than were apparent diffusion coefficient measures. CONCLUSION: Findings from this investigation support the use of diffusion tensor imaging for noninvasive MR imaging measurement of neuropathologic changes in studies of HIV-associated cognitive impairment.

Health of U.S. Navy submarine crew during periods of isolation.

BACKGROUND: An essential element in planning for long-term space missions is prediction of the medical support required. Medical data for analogous populations serving in isolated and/or contained environments are useful in predicting health risks for astronauts. METHODS: This study evaluated the rates of health events that occurred among a highly screened, healthy military population during periods of isolation using a centralized database of medical encounter records from U.S. Navy submarines. The study population was composed of U.S. Navy officers and enlisted men deployed on 240 submarine patrols between 1 January 1997 and 30 September 2000. RESULTS: A total of 1389 officers and 11,952 enlisted crew members served aboard participating submarines for 215,086 and 1,955,521 person-days at sea, respectively, during the study period. Officers had 214 initial visits to medical staff with 79 re-visits for the same condition during these patrols, while enlisted men had 3345 initial visits and 1549 re-visits. Among officers, the most common category of medical events was respiratory illnesses (primarily upper respiratory infections), followed by injury, musculoskeletal conditions, infectious diseases, symptoms and ill-defined conditions, and skin problems. Among enlisted men, the most common category of medical events was injury, followed by respiratory illnesses (upper respiratory infections), skin problems, symptoms and ill-defined conditions, digestive disorders, infectious conditions, sensory organ problems (ear infections and eye problems), and musculoskeletal conditions. CONCLUSIONS: Potential mission-impacting medical events reported were rare, i.e., among a crew of seven officers, only one medical event would be expected to occur during a 6-mo mission and result in 3/4 d or less of limited or no duty. Among a crew of seven enlisted men, about two medical events would be expected during a 6-mo mission and result in about 1 d of limited or no duty per medical event.