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Werner Irnich, Gender differences in pacemaker therapy, EP Europace, Volume 12, Issue 8, August 2010, Pages 1202–1203, https://doi.org/10.1093/europace/euq114
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Nowak and Misselwitz 1 state in their paper on Gender difference: ‘Unfortunately, our data does not allow us to provide a reliable explanation for these gender differences’. Nielsen 2 utters in his Editorial that ‘the difference observed between men and women regarding the pacing mode selection has not been found in previous large cohort studies’ and he adds that ‘the reason for this difference among genders is largely unknown’.
We have investigated the problem of ‘gender bias’ in several papers 3–6 in which we described gender differences and tried to find an explanation for the female ‘discrimination’. We found in a study that pacemaker-dependent women with AV block had 1.17 times more VVI pulse generators when compared with the corresponding male group, whereas this ratio was 1.22 for non-dependent patients. With the indication SSS, the ratio was 1.08. 4
Investigating different age groups on the basis of 21 968 new implant registrations in 1997, it could be seen that the recommendations of guidelines are observed in younger patients, but these are no longer true for older ones. 5 Gender bias exists only in the age group of >80 years. Below, there is only a marginal difference in mode selection. 6 In large clinics (more implantations than mean), the pacemaker population is younger and men or women are better treated with physiological pacemakers when compared with small clinics (less than mean). Between 55 and 95 years, the percentage of VVI pacemakers increased from 50 to 90% almost linearly for patients with implantation during the period 1990 and 1993 corresponding to an increase of 1% per year irrespective of gender. 3 This means that there are three trends responsible for ‘discrimination’ of older women with respect to pacemaker mode selection: Gender differences are, therefore, no ‘discrimination’ but a social problem mainly caused by the fact that women >80 years are treated in smaller clinics in the immediate vicinity of their home possibly arranged by relatives or the care-taking people of senior homes.
with increasing age, the quality of mode selection is decreased,
quality of mode selection decreases in clinics with decreasing implantation numbers, and
women aged >80 years are predominantly treated in smaller clinics.
One striking difference in gender is not mentioned by Nowak and Misselwitz and Nielsen that we found in the past. Men possess in all age groups a pacemaker implantation incidence that is nearly two-fold higher than that for women. 3 , 4 For the population of 17 826 patients reported by Nowak and Misselwitz, one can calculate the relative risk for pacemaker patients with respect to the normal population of Germany in 2006. 7 Using the same age groups as reported under results of the article of Nowak and Misselwitz, 1 the relative risk can be calculated. The calculation formulae are explained in the Appendix.
The portion of the living males and females in Hessen is assumed to be the K th part of that of Germany in all age groups ( K = 7.38% in 2006). The results calculated under the outlined assumptions are listed in Table 1 . Males have a higher risk that lies between 1.7 and 2.0, the weighted mean is 1.75 for Hessen (see last column in Table 1 ).
Age distribution in Germany and the relative risk to be pacemaker patient calculated for males and females (data for 2006) 7
| n . | Age group . | Males, M (in 10 6 ) . | Females, F (in 10 6 ) . | Total (in 10 6 ) . | R1 (F/M, n ) a . | Portion PM(M) . | Portion PM(F) . | R2 (F/M, n ) b . | RR n (F/M) c . | RR n (M/F) d . |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | <60 | 31.392 | 30.329 | 61.721 | 0.966 | 64.1% | 35.9% | 0.560 | 0.580 | 1.724 |
| 2 | 60–69 | 4.729 | 5.064 | 9.793 | 1.071 | 65.1% | 34.9% | 0.536 | 0.504 | 1.984 |
| 3 | 70–79 | 3.083 | 3.953 | 7.036 | 1.282 | 56.5% | 43.5% | 0.770 | 0.600 | 1.667 |
| 4 | 80–89 | 0.973 | 2.264 | 3.237 | 2.327 | 42.4% | 57.6% | 1.358 | 0.584 | 1.712 |
| 5 | ≥90 | 0.134 | 0.435 | 0.569 | 3.246 | 38.4% | 61.6% | 1.604 | 0.494 | 2.024 |
| All | 42.045 | 42.045 | 82.356 | 1.043 | Mean | 0.572 | 1.747 |
| n . | Age group . | Males, M (in 10 6 ) . | Females, F (in 10 6 ) . | Total (in 10 6 ) . | R1 (F/M, n ) a . | Portion PM(M) . | Portion PM(F) . | R2 (F/M, n ) b . | RR n (F/M) c . | RR n (M/F) d . |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | <60 | 31.392 | 30.329 | 61.721 | 0.966 | 64.1% | 35.9% | 0.560 | 0.580 | 1.724 |
| 2 | 60–69 | 4.729 | 5.064 | 9.793 | 1.071 | 65.1% | 34.9% | 0.536 | 0.504 | 1.984 |
| 3 | 70–79 | 3.083 | 3.953 | 7.036 | 1.282 | 56.5% | 43.5% | 0.770 | 0.600 | 1.667 |
| 4 | 80–89 | 0.973 | 2.264 | 3.237 | 2.327 | 42.4% | 57.6% | 1.358 | 0.584 | 1.712 |
| 5 | ≥90 | 0.134 | 0.435 | 0.569 | 3.246 | 38.4% | 61.6% | 1.604 | 0.494 | 2.024 |
| All | 42.045 | 42.045 | 82.356 | 1.043 | Mean | 0.572 | 1.747 |
aR1 (F/M, n ) is the ratio of females to males in the age group n .
bR2 (F/M, n ) is the ratio of PM(F) to PM(M) in the age group n .
c RR n (F/M) is the relative risk of males when compared with females.
d RR n (M/F) is the relative risk of females when compared with males.
Age distribution in Germany and the relative risk to be pacemaker patient calculated for males and females (data for 2006) 7
| n . | Age group . | Males, M (in 10 6 ) . | Females, F (in 10 6 ) . | Total (in 10 6 ) . | R1 (F/M, n ) a . | Portion PM(M) . | Portion PM(F) . | R2 (F/M, n ) b . | RR n (F/M) c . | RR n (M/F) d . |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | <60 | 31.392 | 30.329 | 61.721 | 0.966 | 64.1% | 35.9% | 0.560 | 0.580 | 1.724 |
| 2 | 60–69 | 4.729 | 5.064 | 9.793 | 1.071 | 65.1% | 34.9% | 0.536 | 0.504 | 1.984 |
| 3 | 70–79 | 3.083 | 3.953 | 7.036 | 1.282 | 56.5% | 43.5% | 0.770 | 0.600 | 1.667 |
| 4 | 80–89 | 0.973 | 2.264 | 3.237 | 2.327 | 42.4% | 57.6% | 1.358 | 0.584 | 1.712 |
| 5 | ≥90 | 0.134 | 0.435 | 0.569 | 3.246 | 38.4% | 61.6% | 1.604 | 0.494 | 2.024 |
| All | 42.045 | 42.045 | 82.356 | 1.043 | Mean | 0.572 | 1.747 |
| n . | Age group . | Males, M (in 10 6 ) . | Females, F (in 10 6 ) . | Total (in 10 6 ) . | R1 (F/M, n ) a . | Portion PM(M) . | Portion PM(F) . | R2 (F/M, n ) b . | RR n (F/M) c . | RR n (M/F) d . |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | <60 | 31.392 | 30.329 | 61.721 | 0.966 | 64.1% | 35.9% | 0.560 | 0.580 | 1.724 |
| 2 | 60–69 | 4.729 | 5.064 | 9.793 | 1.071 | 65.1% | 34.9% | 0.536 | 0.504 | 1.984 |
| 3 | 70–79 | 3.083 | 3.953 | 7.036 | 1.282 | 56.5% | 43.5% | 0.770 | 0.600 | 1.667 |
| 4 | 80–89 | 0.973 | 2.264 | 3.237 | 2.327 | 42.4% | 57.6% | 1.358 | 0.584 | 1.712 |
| 5 | ≥90 | 0.134 | 0.435 | 0.569 | 3.246 | 38.4% | 61.6% | 1.604 | 0.494 | 2.024 |
| All | 42.045 | 42.045 | 82.356 | 1.043 | Mean | 0.572 | 1.747 |
aR1 (F/M, n ) is the ratio of females to males in the age group n .
bR2 (F/M, n ) is the ratio of PM(F) to PM(M) in the age group n .
c RR n (F/M) is the relative risk of males when compared with females.
d RR n (M/F) is the relative risk of females when compared with males.
Conflict of interest: none declared.
Appendix
Calculation of the relative risk
RR n (F/M) = I ( n ,F): I ( n ,M) = [ N ( n ,F)/kP( n ,F)]:[ N ( n ,M)/kP( n ,M)] = [ N ( n ,F)/ N ( n ,M)] × [ P ( n ,M)/ P ( n ,F)]
where RR n (F/M) is the relative risk of the n th female age group when compared with that of males; I ( n ,F) the implantation incidence of the n th female age group; I ( n ,M) the implantation incidence of the n th male age group; N ( n ,F) the number of PM patients of the n th female age group; N ( n ,M) the number of PM patients of the n th male age group; kP( n ,F) the K th portion of the female German population in the age group n living in Hessen; kP( n ,F) the K th portion of the male German population in the age group n living in Hessen; N ( n ,F) the number of PM implanted in females in the age group n ; N ( n ,F) the number of PM implanted in males in the age group n ; RR n (M/F) the reciprocal value of RR n (F/M).
