Dr. Ron’s Research Review – October 20, 2010

This week’s research review contains articles on the issue of vaccinations to prevent CAD; and Guidelines for Parenteral Nutrition.

Vaccinations and CAD

A British study suggested that influenza vaccination is associated with a reduced rate of first acute myocardial infarction. (Siriwardena, Gwini et al. 2010)

Several researchers have found problems with the study. I’ve included a news article. (Simonsen 2010)

A study published in JAMA found that pneumococcal vaccine was not associated with subsequent reduced risk of acute MI and stroke (Tseng, Slezak et al. 2010)

A critique of the study appeared in the same issue. (Madjid and Musher 2010)

Guidelines for Parenteral Nutrition.

Lipid emulsions (Adolph, Heller et al. 2009)

Water, electrolytes, vitamins and trace elements. (Biesalski, Bischoff et al. 2009)

Complications and monitoring. (Hartl, Jauch et al. 2009)

Amino acids. (Stein, Boehles et al. 2009)

Dr. Ron


Articles

Influenza vaccination, pneumococcal vaccination and risk of acute myocardial infarction: matched case-control study

            (Siriwardena, Gwini et al. 2010) Download

BACKGROUND: Previous studies have shown an association between acute myocardial infarction and preceding respiratory infection. Contradictory evidence exists on the influence of influenza vaccination and pneumococcal vaccination in preventing cardiovascular disease. We aimed to investigate the possible association of influenza vaccination and pneumococcal vaccination with acute myocardial infarction. METHODS: We used a matched case-control design with data from the United Kingdom General Practice Research Database. Cases were patients who were at least 40 years of age at diagnosis of first acute myocardial infarction recorded from Nov.1, 2001, to May 31, 2007, and were matched for sex, general practice, age and calendar time (i.e., month corresponding to index date of acute myocardial infarction), with up to four controls each. Data were analyzed using conditional logistic regression, adjusted for vaccination target groups, cardiovascular risk factors, treatment medications and attendances at a general practice. RESULTS: We included 78 706 patients, of whom 16 012 were cases and 62 694 were matched controls. Influenza vaccination had been received in the previous year by 8472 cases (52.9%) and 32 081 controls (51.2%) and was associated with a 19% reduction in the rate of acute myocardial infarction (adjusted odds ratio [OR] 0.81, 95% confidence interval [CI] 0.77-0.85). Early seasonal influenza vaccination was associated with a lower rate of acute myocardial infarction (adjusted OR 0.79, 95% CI 0.75-0.83) than vaccination after mid-November (adjusted OR 0.88, 95% CI 0.79-0.97). Pneumococcal vaccination was not associated with a reduction in the rate of acute myocardial infarction (adjusted OR 0.96, 95% CI 0.91-1.02). INTERPRETATION: Influenza vaccination but not pneumococcal vaccination is associated with a reduced rate of first acute myocardial infarction. This association and the potential benefit of early seasonal vaccination need to be considered in future experimental studies.

Lowered heart attack risk-flu vaccination link called into question

            Simonsen 2010 Download

Preventing myocardial infarction with vaccination

            (Madjid and Musher 2010) Download

Pneumococcal vaccination and risk of acute myocardial infarction and stroke in men

            (Tseng, Slezak et al. 2010) Download

CONTEXT: Multiple studies have shown that preventing influenza by vaccination reduces the risk of vascular events. However, the effect of pneumococcal polysaccharide vaccine on vascular events remains controversial. OBJECTIVE: To examine the association between pneumococcal vaccination and risk of acute myocardial infarction (MI) and stroke among men. DESIGN, SETTING, AND PARTICIPANTS: A prospective cohort study of Kaiser Permanente Northern and Southern California health plans with 84 170 participants aged 45 to 69 years from the California Men's Health Study who were recruited between January 2002 and December 2003, and followed up until December 31, 2007. The cohort was similar to the population of health plan members and men who responded to a general health survey in California on important demographic and clinical characteristics. Demographic and detailed lifestyle characteristics were collected from surveys. Vaccination records were obtained from the Kaiser Immunization Tracking System. MAIN OUTCOME MEASURE: Incidence of acute MI and stroke during the follow-up period in men who had no history of such conditions. RESULTS: During follow-up, there were 1211 first MIs in 112,837 vaccinated person-years (10.73 per 1000 person-years) compared with 1494 first MI events in 246,170 unvaccinated person-years (6.07 per 1000 person-years). For stroke, there were 651 events in 122,821 vaccinated person-years (5.30 per 1000 person-years) compared with 483 events in 254,541 unvaccinated person-years (1.90 per 1000 person-years). With propensity score adjustment, we found no evidence for an association between pneumococcal vaccination and reduced risk of acute MI (adjusted hazard ratio [HR], 1.09; 95% confidence interval [CI], 0.98-1.21) or stroke (adjusted HR, 1.14; 95% CI, 1.00-1.31). An inverse association was also not found in men of different age and risk groups. The results appeared to be consistent, because using more specific International Classification of Diseases, Ninth Revision codes for the outcome definition did not change the estimations. CONCLUSION: Among a cohort of men aged 45 years or older, receipt of pneumococcal vaccine was not associated with subsequent reduced risk of acute MI and stroke.


Lipid emulsions - Guidelines on Parenteral Nutrition, Chapter 6

            (Adolph, Heller et al. 2009) Download

The infusion of lipid emulsions allows a high energy supply, facilitates the prevention of high glucose infusion rates and is indispensable for the supply with essential fatty acids. The administration of lipid emulsions is recommended within < or =7 days after starting PN (parenteral nutrition) to avoid deficiency of essential fatty acids. Low-fat PN with a high glucose intake increases the risk of hyperglycaemia. In parenterally fed patients with a tendency to hyperglycaemia, an increase in the lipid-glucose ratio should be considered. In critically ill patients the glucose infusion should not exceed 50% of energy intake. The use of lipid emulsions with a low phospholipid/triglyceride ratio is recommended and should be provided with the usual PN to prevent depletion of essential fatty acids, lower the risk of hyperglycaemia, and prevent hepatic steatosis. Biologically active vitamin E (alpha-tocopherol) should continuously be administered along with lipid emulsions to reduce lipid peroxidation. Parenteral lipids should provide about 25-40% of the parenteral non-protein energy supply. In certain situations (i.e. critically ill, respiratory insufficiency) a lipid intake of up to 50 or 60% of non-protein energy may be reasonable. The recommended daily dose for parenteral lipids in adults is 0.7-1.3 g triglycerides/kg body weight. Serum triglyceride concentrations should be monitored regularly with dosage reduction at levels >400 mg/dl (>4.6 mmol/l) and interruption of lipid infusion at levels >1000 mg/dl (>11.4 mmol/l). There is little evidence at this time that the choice of different available lipid emulsions affects clinical endpoints.

Water, electrolytes, vitamins and trace elements - Guidelines on Parenteral Nutrition, Chapter 7

            (Biesalski, Bischoff et al. 2009) Download

A close cooperation between medical teams is necessary when calculating the fluid intake of parenterally fed patients. Fluids supplied parenterally, orally and enterally, other infusions, and additional fluid losses (e.g. diarrhea) must be considered. Targeted diagnostic monitoring (volume status) is required in patients with disturbed water or electrolyte balance. Fluid requirements of adults with normal hydration status is approximately 30-40 ml/kg body weight/d, but fluid needs usually increase during fever. Serum electrolyte concentrations should be determined prior to PN, and patients with normal fluid and electrolyte balance should receive intakes follwing standard recommendations with PN. Additional requirements should usually be administered via separate infusion pumps. Concentrated potassium (1 mval/ml) or 20% NaCl solutions should be infused via a central venous catheter. Electrolyte intake should be adjusted according to the results of regular laboratory analyses. Individual determination of electrolyte intake is required when electrolyte balance is initially altered (e.g. due to chronic diarrhea, recurring vomiting, renal insufficiency etc.). Vitamins and trace elements should be generally substituted in PN, unless there are contraindications. The supplementation of vitamins and trace elements is obligatory after a PN of >1 week. A standard dosage of vitamins and trace elements based on current dietary reference intakes for oral feeding is generally recommended unless certain clinical situations require other intakes.

Complications and monitoring - Guidelines on Parenteral Nutrition, Chapter 11

            (Hartl, Jauch et al. 2009) Download

Compared to enteral or hypocaloric oral nutrition, the use of PN (parenteral nutrition) is not associated with increased mortality, overall frequency of complications, or longer length of hospital stay (LOS). The risk of PN complications (e.g. refeeding-syndrome, hyperglycaemia, bone demineralisation, catheter infections) can be minimised by carefully monitoring patients and the use of nutrition support teams particularly during long-term PN. Occuring complications are e.g. the refeeding-syndrome in patients suffering from severe malnutrition with the initiation of refeeding or metabolic, hypertriglyceridemia, hyperglycaemia, osteomalacia and osteoporosis, and hepatic complications including fatty liver, non-alcoholic fatty liver disease, cholestasis, cholecystitis, and cholelithiasis. Efficient monitoring in all types of PN can result in reduced PN-associated complications and reduced costs. Water and electrolyte balance, blood sugar, and cardiovascular function should regularly be monitored during PN. Regular checks of serum electrolytes and triglycerides as well as additional monitoring measures are necessary in patients with altered renal function, electrolyte-free substrate intake, lipid infusions, and in intensive care patients. The metabolic monitoring of patients under long-term PN should be carried out according to standardised procedures. Monitoring metabolic determinants of bone metabolism is particularly important in patients receiving long-term PN. Markers of intermediary, electrolyte and trace element metabolism require regular checks.

Amino acids - Guidelines on Parenteral Nutrition, Chapter 4

            (Stein, Boehles et al. 2009) Download

Protein catabolism should be reduced and protein synthesis promoted with parenteral nutrion (PN). Amino acid (AA) solutions should always be infused with PN. Standard AA solutions are generally used, whereas specially adapted AA solutions may be required in certain conditions such as severe disorders of AA utilisation or in inborn errors of AA metabolism. An AA intake of 0.8 g/kg/day is generally recommended for adult patients with a normal metabolism, which may be increased to 1.2-1.5 g/kg/day, or to 2.0 or 2.5 g/kg/day in exceptional cases. Sufficient non-nitrogen energy sources should be added in order to assure adequate utilisation of AA. A nitrogen calorie ratio of 1:130 to 1:170 (g N/kcal) or 1:21 to 1:27 (g AA/kcal) is recommended under normal metabolic conditions. In critically ill patients glutamine should be administered parenterally if indicated in the form of peptides, for example 0.3-0.4 g glutamine dipeptide/kg body weight/day (=0.2-0.26 g glutamine/kg body weight/day). No recommendation can be made for glutamine supplementation in PN for patients with acute pancreatitis or after bone marrow transplantation (BMT), and in newborns. The application of arginine is currently not warranted as a supplement in PN in adults. N-acetyl AA are only of limited use as alternative AA sources. There is currently no indication for use of AA solutions with an increased content of glycine, branched-chain AAs (BCAA) and ornithine-alpha-ketoglutarate (OKG) in all patients receiving PN. AA solutions with an increased proportion of BCAA are recommended in the treatment of hepatic encephalopathy (III-IV).


References

Adolph, M., A. R. Heller, et al. (2009). "Lipid emulsions - Guidelines on Parenteral Nutrition, Chapter 6." Ger Med Sci 7: Doc22.

Biesalski, H. K., S. C. Bischoff, et al. (2009). "Water, electrolytes, vitamins and trace elements - Guidelines on Parenteral Nutrition, Chapter 7." Ger Med Sci 7: Doc21.

Hartl, W. H., K. W. Jauch, et al. (2009). "Complications and monitoring - Guidelines on Parenteral Nutrition, Chapter 11." Ger Med Sci 7: Doc17.

Madjid, M. and D. M. Musher (2010). "Preventing myocardial infarction with vaccination: myths and realities." JAMA 303(17): 1751-2.

Siriwardena, A. N., S. M. Gwini, et al. (2010). "Influenza vaccination, pneumococcal vaccination and risk of acute myocardial infarction: matched case-control study." CMAJ.

Stein, J., H. J. Boehles, et al. (2009). "Amino acids - Guidelines on Parenteral Nutrition, Chapter 4." Ger Med Sci 7: Doc24.

Tseng, H. F., J. M. Slezak, et al. (2010). "Pneumococcal vaccination and risk of acute myocardial infarction and stroke in men." JAMA 303(17): 1699-706.