Thomas E. Feasby

Coding algorithms for defining comorbidities in ICD-9-CM and ICD-10 administrative data.

Objectives:Implementation of the International Statistical Classification of Disease and Related Health Problems, 10th Revision (ICD-10) coding system presents challenges for using administrative data. Recognizing this, we conducted a multistep process to develop ICD-10 coding algorithms to define Charlson and Elixhauser comorbidities in administrative data and assess the performance of the resulting algorithms. Methods:ICD-10 coding algorithms were developed by “translation” of the ICD-9-CM codes constituting Deyos (for Charlson comorbidities) and Elixhausers coding algorithms and by physicians’ assessment of the face-validity of selected ICD-10 codes. The process of carefully developing ICD-10 algorithms also produced modified and enhanced ICD-9-CM coding algorithms for the Charlson and Elixhauser comorbidities. We then used data on in-patients aged 18 years and older in ICD-9-CM and ICD-10 administrative hospital discharge data from a Canadian health region to assess the comorbidity frequencies and mortality prediction achieved by the original ICD-9-CM algorithms, the enhanced ICD-9-CM algorithms, and the new ICD-10 coding algorithms. Results:Among 56,585 patients in the ICD-9-CM data and 58,805 patients in the ICD-10 data, frequencies of the 17 Charlson comorbidities and the 30 Elixhauser comorbidities remained generally similar across algorithms. The new ICD-10 and enhanced ICD-9-CM coding algorithms either matched or outperformed the original Deyo and Elixhauser ICD-9-CM coding algorithms in predicting in-hospital mortality. The C-statistic was 0.842 for Deyos ICD-9-CM coding algorithm, 0.860 for the ICD-10 coding algorithm, and 0.859 for the enhanced ICD-9-CM coding algorithm, 0.868 for the original Elixhauser ICD-9-CM coding algorithm, 0.870 for the ICD-10 coding algorithm and 0.878 for the enhanced ICD-9-CM coding algorithm. Conclusions:These newly developed ICD-10 and ICD-9-CM comorbidity coding algorithms produce similar estimates of comorbidity prevalence in administrative data, and may outperform existing ICD-9-CM coding algorithms.

Medical and Neurological Complications of Ischemic Stroke Experience From the RANTTAS Trial

BACKGROUND AND PURPOSE Medical and neurological complications after acute ischemic stroke may adversely impact outcome and in some cases may be preventable. Limited data exist regarding the frequency of such complications occurring in the first days after the ictus and the relationship of these complications to outcome. Our objective was to identify the types, severity, and frequency of medical and neurological complications following acute ischemic stroke and to determine their role in mortality and functional outcome. METHODS Rates of serious (life-threatening) and nonserious medical and neurological complications and mortality were derived from the placebo limb of the Randomized Trial of Tirilazad Mesylate in Acute Stroke (RANTTAS) database (n=279). Complications were correlated with clinical outcome using logistic regression techniques. RESULTS Of all patients, 95% had at least one complication. The most common serious medical complication was pneumonia (5%), and the most common serious neurological complication was new cerebral infarction or extension of the admission infarction (5%). The 3-month mortality was 14%; 51% of these deaths were attributed primarily to medical complications. Outcome was significantly worse in patients with serious medical complications, after adjustment for baseline imbalances, as measured by the Barthel Index (odds ratio [OR], 6.1; 95% confidence interval [CI], 2.5 to 15.1) and by the Glasgow Outcome Scale (OR, 11.6; 95% CI, 4.3 to 30.9). After death was discounted, serious medical complications were associated with severe disability at 3 months as determined by the Glasgow Outcome Scale (OR, 4.4; 95% CI, 1.3 to 14.8). CONCLUSIONS Medical complications that follow ischemic stroke not only influence mortality but may influence functional outcome.

Multifocal motor neuropathy improved by IVIg Randomized, double-blind, placebo-controlled study

Objective: To determine the effect of IV immunoglobulin (IVIg) on neurologic function and electrophysiologic studies in multifocal motor neuropathy with conduction block (MMN). Background: MMN is characterized by progressive, asymmetric, lower motor neuron weakness and is probably immune-mediated. IVIg treatment has been shown to have beneficial effects in several open-label studies and in one small controlled trial. However, larger randomized controlled studies are lacking. Methods: The authors recruited 16 patients with MMN. All subjects were given each of two treatments (IVIg [0.4 g/kg/d for 5 consecutive days] or placebo [dextrose or saline]) that were assigned according to a randomized, crossover design under double-blind conditions. Patients were evaluated before and about 28 days after trial treatment for subjective functional improvement, neurologic disability score, grip strength, distal and proximal compound muscle action potential amplitude, and conduction block. Results: Subjective functional improvement with IVIg treatment was rated as dramatic or very good in nine patients, moderate in one, mild in one, and absent in five patients. This improvement was absent after placebo. The neurologic disability score improved by 6.7 ± 3.3 points with IVIg treatment, whereas it decreased by 2.1 ± 3.0 with placebo (p = 0.038). Grip strength on the weaker side was increased by 6.4 ±1.9 kg with IVIg treatment; it decreased by 1.0 ± 0.8 kg with placebo (p = 0.0021). Conduction block worsened by 12.98 ± 6.52 % with placebo, but improved by 12.68 ± 5.62 % with IVIg treatment (p = 0.037). Conduction block was reversed in five patients with IVIg but not placebo. Conclusion: IVIg improved conduction block as well as subjective and objective clinical measures of function in patients with MMN.

Statins Are Associated With Better Outcomes After Carotid Endarterectomy in Symptomatic Patients

Background and Purpose— Statins have been associated with a reduction in mortality from noncardiac surgery. This study aimed to determine whether statin use on admission to hospital for carotid endarterectomy was associated with a reduction of in-hospital adverse outcomes. Methods— Data describing patient characteristics, surgical indication, statin treatment, and in-hospital outcomes of death, ischemic stroke or death and cardiac outcomes were collected from a chart review of all patients (3360) undergoing carotid endarterectomy in Western Canada from January 2000 to December 2001. Outcomes of patients on statins versus those not on statins were compared using logistic regression to account for differences in patient characteristics, and propensity score methods to account for factors influencing patient allocation to statins. Results— Eight hundred and fifteen of 2031 symptomatic patients and 665 of 1252 asymptomatic patients were on a statin at the time of hospital admission. Statin use by symptomatic patients was associated with reduced in-hospital mortality and in-hospital ischemic stroke or death, but not in-hospital cardiac outcomes (adjusted odds ratio 0.25 [CI, 0.07 to 0.90], 0.55 [CI, 0.32 to 0.95], 0.87 [CI, 0.49 to 1.54], respectively). The improvement in outcomes was robust when tested using propensity score matching. This association was not seen in asymptomatic patients on statins (adjusted odds ratio, in-hospital mortality 0.54 [CI, 0.13 to 2.24]; in-hospital ischemic stroke or death 1.34 [CI, 0.61 to 2.93]; in-hospital cardiac outcomes 1.37 [CI, 0.73 to 2.58]). Conclusions— These findings are suggestive of a protective effect of statin therapy in symptomatic patients pre-treated at the time of carotid endarterectomy, though this needs confirmation in a randomized controlled trial.

Effectiveness of t-PA in acute ischemic stroke: Outcome relates to appropriateness

Objective: To examine whether the demonstrated efficacy of tissue-type plasminogen activator (t-PA) for acute ischemic stroke can be effective in a community setting. Methods: Sixty-eight consecutive patients with acute ischemic stroke treated with IV t-PA within 3 hours of symptom onset by attending general neurologists in a busy teaching hospital. Outcome measures at 3 months were the National Institute of Health Stroke Scale (NIHSS), functional outcome (independence [modified Rankin score 0–2], dependence [modified Rankin score 3–5], and death), and symptomatic hemorrhage. Appropriately treated patients were defined by adherence to the National Institute of Neurological Disorders and Stroke (NINDS) guidelines. Effectiveness is expressed as the absolute risk reduction in which the baseline risk is assumed to be similar to that of the NINDS control group. Results: Of 68 consecutively treated patients (with a mean baseline NIHSS score of 15 ± 6), 26 (38%) made a full recovery and 39 (57%) made an independent recovery. The 11 patients who violated protocol had a lower probability of independence (p < 0.02) and full neurologic recovery (p < 0.02) and a higher probability of symptomatic hemorrhage (p < 0.05) and death (p < 0.01) compared with those of 57 patients treated according to NINDS guidelines. Conclusions: The use of t-PA for stroke in this community is effective with a number needed to treat of six. The risk of symptomatic hemorrhage is similar to that noted in randomized trials. Treating patients who violate protocol results in excess risk with no observable benefit.

Severe axonal degeneration in acute Guillain-Barré syndrome : evidence of two different mechanisms ?

Four cases of severe acute Guillain-Barré syndrome (GBS) characterized by severe axonal degeneration are presented. All had electrically inexcitable motor nerves as early as 4 days after onset. The disease was rapid in onset and the residual disability was severe. Two different types of pathology were seen. Nerve biopsies in 3 cases showed severe axonal degeneration without inflammation or demyelination. Autopsy in one of these cases showed that the dorsal and ventral roots were also significantly affected. These cases illustrate the primary axonal form of GBS. Nerve biopsy in the fourth case at day 15 showed marked inflammation and demyelination with axonal degeneration. Contralateral nerve biopsy at day 75 showed almost complete loss of axons. This case illustrates another type of axonal degeneration, that which occurs secondary to inflammation and demyelination.

Multiple sclerosis after age 50

When multiple sclerosis (MS) presents late in life (after the age of 50), it frequently gives diagnostic difficulty. In a large MS clinic population (N = 838), 9.4% of the patients had late onset of MS. Slow deterioration of motor function characterized the initial symptoms and subsequent course of this group of older patients. Progression of disability was more rapid than in younger patients. Evoked response studies and CSF electrophoresis were of high diagnostic yield in the older patient group. Reasons for the differing clinical features in the late-onset patients are discussed. We suggest that the age-of-onset criterion for MS be raised to 60 in adequately investigated cases.

Passive transfer studies in Guillain‐Barre polyneuropathy

Serum and lymphocytes from patients with acute Guillain-Barre polyneuropathy were injected into rat sciatic nerves. Serum from 13 of 17 patients produced perivenular demyelination, associated with lymphocytic infiltration. The pattern of demyelination differed from that caused by experimental allergic neuritis serum. The level of serum demyelinating activity was greatest early in the disease and then decreased. The demyelinating factor was heat-labile but not complement-dependent. Circulating lymphocytes did not cause demyelination in eight patients.

Association between chronic cerebrospinal venous insufficiency and multiple sclerosis: a meta-analysis

Background: It has been proposed by Zamboni and colleagues that multiple sclerosis is caused by chronic cerebrospinal venous insufficiency, a term used to describe ultrasound-detectable abnormalities in the anatomy and flow of intra- and extracerebral veins. We conducted a meta-analysis of studies that reported the frequency of chronic cerebrospinal venous insufficiency among patients with and those without multiple sclerosis. Methods: We searched MEDLINE and EMBASE as well as bibliographies of relevant articles for eligible studies. We included studies if they used ultrasound to diagnose chronic cerebrospinal venous insufficiency and compared the frequency of the venous abnormalities among patients with and those without multiple sclerosis. Results: We identified eight eligible studies: all included healthy controls, and four of them also included a control group of patients with neurologic diseases other than multiple sclerosis. Chronic cerebrospinal venous insufficiency was more frequent among patients with multiple sclerosis than among the healthy controls (odds ratio [OR] 13.5, 95% confidence interval [CI] 2.6–71.4), but there was extensive unexplained heterogeneity among the studies. The association remained significant in the most conservative sensitivity analysis (OR 3.7, 95% CI 1.2–11.0), in which we removed the initial study by Zamboni and colleagues and added a study that did not find chronic cerebrospinal venous insufficiency in any patient. Although chronic cerebrospinal venous insufficiency was also more frequent among patients with multiple sclerosis than among controls with other neurologic diseases (OR 32.5, 95% CI 0.6–1775.7), the association was not statistically significant, the 95% CI was wide, and the OR was less extreme after removal of the study by Zamboni and colleagues (OR 3.5, 95% 0.8–15.8). Interpretation: Our findings showed a positive association between chronic cerebrospinal venous insufficiency and multiple sclerosis. However, poor reporting of the success of blinding and marked heterogeneity among the studies included in our review precluded definitive conclusions.

Passive transfer of demyelination by experimental allergic neuritis serum

SummarySerum from rabbits with experimental allergic neuritis (FAN) when injected into rat sciatic nerves produced rapidly evolving demyelination followed by remyelination. Myelinating and non-myelinating Schwann cells as well as myelin itself were damaged by 15 min after injection. Myelin degradation was well advanced prior to involvement by macrophages at 12 h. The demyelinating factor was myelin-specific and complement-dependent. The evidence suggests that the FAN antigen may reside in Schwann cell membranes as well as in myelin.