Association of Hospital-Diagnosed Infections and Antibiotic Use With Risk of Developing Guillain-Barré Syndrome

Hospital-diagnosed morbidities and recent surgery as risk factors for developing Guillain-Barré syndrome

BACKGROUND AND PURPOSE

This study was undertaken to determine the association of hospital-diagnosed morbidity and recent surgery with risk of subsequent Guillain-Barré syndrome (GBS) development.

METHODS

We conducted a nationwide population-based case-control study of all patients with first-time hospital-diagnosed GBS in Denmark between 2004 and 2016 and 10 age-, sex-, and index date-matched population controls per case. Hospital-diagnosed morbidities included in the Charlson Comorbidity Index were assessed as GBS risk factors up to 10 years prior to the GBS index date. Incident major surgery was assessed within 5 months prior.

RESULTS

In the 13-year study period, there were 1086 incident GBS cases, whom we compared with 10,747 matched controls. Any pre-existing hospital-diagnosed morbidity was observed in 27.5% of GBS cases and 20.0% of matched controls, yielding an overall matched odds ratio (OR) of 1.6 (95% confidence interval [CI] = 1.4-1.9). The strongest associations were found for leukemia, lymphoma, diabetes, liver disease, myocardial infarction, congestive heart failure, and cerebrovascular disease, with 1.6- to 4.6-fold increased risks of subsequent GBS. GBS risk was strongest for morbidities newly diagnosed during the past 5 months (OR = 4.1, 95% CI = 3.0-5.6). Surgical procedures within 5 months prior were observed in 10.6% of cases and 5.1% of controls, resulting in a GBS OR of 2.2 (95% CI = 1.8-2.7). Risk of developing GBS was highest during the first month following surgery (OR = 3.7, 95% CI = 2.6-5.2).

CONCLUSIONS

In this large nationwide study, individuals with hospital-diagnosed morbidity and recent surgery had a considerably increased risk of GBS.

Guillain-Barré syndrome following influenza vaccination: A 15-year nationwide population-based case-control study

BACKGROUND AND PURPOSE

Influenza vaccination may increase the risk of developing Guillain-Barré syndrome (GBS) due to an elicited immune response, but the exact magnitude and duration of risk is unclear and hence the aim of this study.

METHODS

We conducted a retrospective nationwide population-based case-control study of prospectively collected data on all patients with first-time hospital-diagnosed GBS in Denmark between 2002 and 2016 and 10 age-, sex- and index date-matched population controls per case. The primary exposure was incident influenza vaccination 1 month prior to admission with GBS. We used medical registries to ascertain a complete hospital contact history of pre-existing morbidities. To examine duration of GBS risk, we repeated the analysis for five consecutive 1-month risk periods following vaccination.

RESULTS

Of the 1295 GBS cases and 12,814 controls, 20 cases (1.5%) and 119 controls (0.9%) had received an influenza vaccination within the last month, yielding a comorbidity-adjusted odds ratio of 1.9 (95% confidence interval 1.1-3.2) for GBS. Stratified analyses by calendar time, gender and age showed similar results. The increased risk of GBS was largely confined to 1 month following influenza vaccination. The population-attributable fraction of GBS from influenza vaccination in Denmark was 0.4%.

CONCLUSIONS

Influenza vaccination was associated with a slightly elevated risk of GBS occurrence within 1 month after vaccination. However, only 1.5% of GBS cases in Denmark are associated with recent influenza vaccination. Thus, the benefit of influenza vaccines in preventing influenza infections and associated morbidity and mortality needs to be weighed against the small absolute risk of GBS.

Association Between Incident Cancer and Guillain-Barré Syndrome Development: A Nationwide Case-Control Study

BACKGROUND AND OBJECTIVES

Cancer may increase the risk of developing Guillain-Barré syndrome (GBS) due to molecular mimicry or immunosuppression, but the exact relationship is unclear. We aimed to determine the association between incident cancer and the following risk of GBS development.

METHODS

We conducted a nationwide population-based case-control study of all patients with first-time hospital-diagnosed GBS in Denmark between 1987 and 2016 and 10 age, sex and index date-matched population controls per case. We identified incident cancer diagnoses between six months prior to and two months after the GBS index date. We used conditional logistic regression to compute ORs as a measure of relative risk and performed stratified analyses to assess the impact of cancer on GBS risk in strata of calendar-periods, sex and age. In sensitivity analyses, to assess any potential risk of survival bias induced by including cancer diagnoses potentially made after GBS diagnosis, we examined incident cancers in both a broader exposure window (one year before to three months after GBS index date) and a narrower window (six months to one month before the GBS index date).

RESULTS

Of the 2,414 patients with GBS and 23,909 controls included, 49 cases (2.0%) and 138 controls (0.6%) had a recent cancer diagnosis, respectively, yielding a matched odds ratio (OR) of 3.6 (95% confidence interval (CI), 2.6- 5.1) for GBS associated with cancer. Stratification by calendar time, gender and age showed robust results for the association between cancer and GBS, with no major variations. Broadening and narrowing the exposure window produced slightly weakened associations of OR, 2.4 (95% CI, 1.8-3.3) and OR, 2.5 (95% CI, 1.5-4.1), respectively. The GBS ORs were highest for cancers of the lymphatic and hematopoietic tissue (OR, 7.2; 95% CI, 2.9-18.0), respiratory tract (OR, 5.6; 95% CI, 2.7-11.9), prostate and other male genital organ (OR, 5.0; 95% CI, 2.1-11.6) and breast cancer (OR, 5.0; 95% CI, 1.7-14.5).

DISCUSSION

In this large nationwide epidemiologic study, incident cancer was associated with a markedly increased risk of subsequent GBS development. The results suggest that yet unidentified factors present in several types of cancer drive this association.

Increased mortality following Guillain-Barré syndrome: A population-based cohort study

BACKGROUND AND PURPOSE

Guillain-Barré syndrome (GBS) may be fatal in the acute phase but also affect long-term prognosis due to irreversible sequelae and secondary medical complications. We determined the short-term, intermediate, and long-term mortality of GBS compared to the general population.

METHODS

Individual-level data from nationwide registries were linked in this matched cohort study of all first-time hospital-diagnosed GBS patients in Denmark between 1987 and 2016 and 10 individuals from the general population, matched on age, sex, and index date. We used Cox regression analysis to calculate matched mortality hazard ratios (HRs) following GBS, assessing short-term (0-6 months), intermediate (>6 months-4 years), and long-term (>4 years) mortality.

RESULTS

We identified 2414 patients with GBS and 23,909 matched individuals from the general population. Short-term mortality was 4.8% (95% confidence interval [CI] = 4.0-5.8) and 0.8% (95% CI = 0.7-0.9) for GBS patients and general population members, respectively, resulting in an HR of 6.6 (95% CI = 4.0-5.8). Intermediate mortality was 7.6% (95% CI = 6.5-8.9), compared with 5.8% (95% CI = 5.5-6.1) for general population members, corresponding to an HR of 1.5 (95% CI = 1.3-1.8). After the first 4 years, long-term mortality showed similar results for GBS patients and general population members (HR = 1.1, 95% CI = 0.9-1.2).

CONCLUSIONS

During the first 6 months after GBS hospital admission, GBS was associated with a 6.6-fold increased mortality as compared with the background population of the same age. Mortality remained increased for approximately 4 years following GBS, and then leveled off to a similar long-term mortality rate.