Three types of analyses were performed to assess the difference in the prevalence of ACS, AHF, arrhythmia, PE and 'Other CVDs' between years 2019 and 2020. All analyses were performed on the whole population and, separately, in context of different sex. The first analysis was performed to assess differences in disease distribution (Table 1, Fig. 1). The second, to check whether the odds ratios for incidence of these diseases differed between the years 2019 and 2020, after stratification based on sex (Table 2, Fig. 2). The last analysis was performed to assess whether the distribution of the subtypes of selected diseases and/or their coincidence with symptoms of heart failure varied in time (Table 3).
3.1.1 Observations on the total, unstratified population
In the total population studied, there were significant differences (Table 1, Fig. 1) in the distributions of the analyzed CVDs (p < 0.00001), as a result of significant increases in the frequency of PE (p ≈ 0.0304), and decreases in AHF (p < 0.00001) and ‘Other CVDs’ (p ≈ 0.0005) from 2019 to 2020. The frequencies of PE in 2020 and 2019 were: 3.35% and 2.57%, respectively. The odds ratio of the incidence of PE among hospitalized patients in 2020 were 1.316-fold greater compared to the odds in 2019 (OR 1.315, 95%CI 1.026–1.689). Interestingly, the frequency of AHF dropped from 2019 to 2020 (11.86% vs. 8.19%). The incidence of AHF among hospitalized patients was 50.83% less likely (OR = 0.663) to be observed in 2020, compared to 2019. The odds for the incidence of Other CVDs increased by 17.42% (OR = 1.1742) between the years 2019 and 2020 (frequencies: 30.65% and 34.16%, respectively).
Although the incidence of ACS did not differ between 2019 and 2020 (p ≈ 0.1265), an interesting observation emerged upon analysis of the distribution of its types: NSTEMI, STEMI and unstable angina, between 2019 and 2020 (p ≈ 0.0001). The odds of incidence of NSTEMI and unstable angina were lower in 2020, compared to 2019 (p-values: 0.0109, 0.0176; ORs: 0.8204, 0.7802 for the incidence of NSTEMI, unstable angina, respectively). Conversely, the odds for the incidence of STEMI were approximately 38.55% higher in 2020 (OR = 1.3855), compared to 2019 (p ≈ 0.00002). De novo AHF was more frequent in 2020, compared to 2019 (OR = 1.589, p ≈ 0.0450), although the significance of this observation was ambiguous (as described in subsection 2.2.). The frequencies are shown in Table 3.
3.1.2 The influence of stratification based on sex on the observations in the total population of hospitalized patients
When the whole population sample was stratified according to sex (Table 2, Fig. 2), a significant difference in the distribution of the aforementioned diseases was observed in men (p < 0.00001). In women, this difference was not significant (p ≈ 0.1037). Interestingly neither men nor women subpopulations showed a significant increase in PE incidence, as was observed in the whole population. Among men, the incidence of AHF was 72.41% less likely (OR = 0.580, p < 0.00001) in 2020 (frequency: 7.89%), compared to 2019 (12.88%). A higher incidence of Other CVDs was observed among men in 2020 (frequency: 31.61%), compared to 2019 (frequency: 27.76%). The odds for the incidence of these diseases in men were 20.24% greater (OR = 1.2024, p ≈ 0.0020) in 2020, compared to 2019. All the previously described observations regarding the incidence of the analyzed CVDs remained statistically significant after accounting for the stratification. The adjusted odds ratios describing the incidence of PE, AHF and Other CVDs are similar to those computed without accounting for stratification (Table 2).
Stratification revealed that STEMI, NSTEMI and unstable angina were differently distributed among men (p ≈ 0.0007), but not in women (p ≈ 0.1160). Nevertheless, analysis of the incidence of each ACS type separately revealed significant differences in both sexes. In men, the incidence of NSTEMI and unstable angina decreased in 2020, compared to 2019 (p-values: 0.0222, 0.0386; ORs: 0.8087, 0.7716 for NSTEMI, unstable angina, respectively). The frequency of STEMI increased by 8.43 percentage points (40.56% increase in odds, OR = 1.4056) in men between the years 2019 and 2020. In women, only the differences in the incidence of STEMI were significant (p ≈ 0.0427), accounting for an increase in the odds for STEMI incidence by 33.51% (OR = 1.3351) between years 2019 and 2020 (frequencies: 37.85% and 44.85% in years: 2019 and 2020, respectively). This finding in women should be interpreted with caution, since the global test for differences in distribution of the types of ACS showed lack of significance (p ≈ 0.1160). The overall odds ratio (describing the entire population sample after accounting for stratification) for the incidence of ACS types between the years 2019 and 2020 is shown in Table 3.
It should be emphasized, that the OR describing the incidence of de novo AHF compared to the incidence of CHF decompensation AHF between the years 2019 and 2020, was insignificant after adjusting for stratification based on sex (p ≈ 0.0542). Therefore, the underlying hypothesis is not likely to be true in the general population (and does not hold in male and female subpopulations either).
Table 1
Time-related frequencies of the selected CVD categories
Overall distribution (regardless of sex, N = 8744) |
Strata | Year: 2019 | Year: 2020 | Year: 2019 | Year: 2020 | χ2 | p |
count [n] | count [n] | frequency [%] | frequency [%] |
ACS | 1530 (1496.24) | 1414 (1447.76) | 34.43 | 32.88 | 44.64 | < 0.00001 |
Arrhythmia | 911 (931.09) | 921 (900.91) | 20.50 | 21.42 |
PE | 114 (131.12) | 144 (126.88) | 2.57 | 3.35 |
AHF | 527 (446.74) | 352 (432.26) | 11.86 | 8.19 |
Other CVDs | 1362 (1438.81) | 1469 (1392.19) | 30.65 | 34.16 |
Subset distribution (sex: female, N = 3333) |
Strata | Year: 2019 | Year: 2020 | Year: 2019 | Year: 2020 | χ2 | p |
count [n] | count [n] | frequency [%] | frequency [%] |
ACS | 454 (431.76) | 415 (437.24) | 27.42 | 24.75 | 7.69 | 0.1037 |
Arrhythmia | 393 (398.47) | 409 (403.53) | 23.73 | 24.39 |
PE | 53 (60.12) | 68 (60.88) | 3.20 | 4.05 |
AHF | 168 (155.51) | 145 (157.49) | 10.14 | 8.65 |
Other CVDs | 588 (610.13) | 640 (617.87) | 35.51 | 38.16 |
Subset distribution (sex: male, N = 5411) |
Strata | Year: 2019 | Year: 2020 | Year: 2019 | Year: 2020 | χ2 | p |
count [n] | count [n] | frequency [%] | frequency [%] |
ACS | 1076 (1069.14) | 999 (1005.86) | 38.59 | 38.09 | 42.25 | < 0.00001 |
Arrhythmia | 518 (530.7) | 512 (499.3) | 18.58 | 19.52 |
PE | 61 (70.59) | 76 (66.41) | 2.19 | 2.90 |
AHF | 359 (291.63) | 207 (274.37) | 12.88 | 7.89 |
Other CVDs | 774 (825.94) | 829 (777.06) | 27.76 | 31.61 |
Numbers in ‘()’ brackets indicate expected (estimated) counts.
Table 2
Time-related differences in incidence of selected CVDs
Overall distribution (regardless of sex, N = 8744) |
Variable | Class | Year: 2019 | Year: 2020 | Year: 2019 | Year: 2020 | χ2 | No stratification corrections | Generalized CMH (adjusted for stratification by sex) |
count [n] | count [n] | frequency [%] | frequency [%] | p | OR | OR {-95% CI} | OR {95% CI} | χ2 | p | OR | OR {-95% CI} | OR {95% CI} |
ACS | ACS | 1530 (1496.24) | 1414 (1447.76) | 34.43 | 32.88 | 2.34 | 0.1265 | - | - | - | 1.76 | 0.1842 | - | - | - |
No ACS | 2914 (2947.76) | 2886 (2852.24) | 65.57 | 67.12 |
Arrhythmia | Arrhythmia | 911 (9319) | 921 (900.91) | 20.50 | 21.42 | 1.11 | 0.2910 | - | - | - | 0.92 | 0.3385 | - | - | - |
No arrhythmia | 3533 (3512.91) | 3379 (3399.09) | 79.50 | 78.58 |
PE | PE | 114 (131.12) | 144 (126.88) | 2.57 | 3.35 | 4.69 | 0.0304 | 1.316 | 1.026 | 1.689 | 4.47 | 0.0346 | 1.308 | 1.019 | 1.678 |
No PE | 4330 (4312.88) | 4156 (4173.12) | 97.43 | 96.65 |
AHF | AHF | 527 (446.74) | 352 (432.26) | 11.86 | 8.19 | 32.60 | < 0.00001 | 0.663 | 0.575 | 0.764 | 32.29 | < 0.00001 | 0.664 | 0.576 | 0.765 |
No AHF | 3917 (3997.26) | 3948 (3867.74) | 88.14 | 91.81 |
Other CVDs | Other CVDs | 1362 (1438.81) | 1469 (1392.19) | 30.65 | 34.16 | 12.33 | 0.0005 | 1.174 | 1.073 | 1.284 | 11.53 | 0.0007 | 1.169 | 1.068 | 1.278 |
ACS/arrhythmia/PE/AHF | 3082 (3005.19) | 2831 (2907.81) | 69.35 | 65.84 |
Subset distribution (sex: female, N = 3333) | | | | | |
Variable | Class | Year: 2019 | Year: 2020 | Year: 2019 | Year: 2020 | χ2 | p | OR | OR {-95% CI} | OR {95% CI} | | | | | |
count [n] | count [n] | frequency [%] | frequency [%] | | | | | |
ACS | ACS | 454 (431.76) | 415 (437.24) | 27.42 | 24.75 | 3.08 | 0.0793 | - | - | - | | | | | |
No ACS | 1202 (1224.24) | 1262 (1239.76) | 72.58 | 75.25 | | | | | |
Arrhythmia | Arrhythmia | 393 (398.47) | 409 (403.53) | 23.73 | 24.39 | 0.20 | 0.6573 | - | - | - | | | | | |
No arrhythmia | 1263 (1257.53) | 1268 (1273.47) | 76.27 | 75.61 | | | | | |
PE | PE | 53 (60.12) | 68 (60.88) | 3.20 | 4.05 | 1.74 | 0.1873 | 1.278 | 0.887 | 1.843 | | | | | |
No PE | 1603 (1595.88) | 1609 (1616.12) | 96.80 | 95.95 | | | | | |
AHF | AHF | 168 (155.51) | 145 (157.49) | 10.14 | 8.65 | 2.20 | 0.1381 | 0.838 | 0.664 | 1.059 | | | | | |
No AHF | 1488 (1500.49) | 1532 (1519.51) | 89.86 | 91.35 | | | | | |
Other CVDs | Other CVDs | 588 (610.13) | 640 (617.87) | 35.51 | 38.16 | 2.53 | 0.1120 | 1.121 | 0.974 | 1.291 | | | | | |
ACS/arrhythmia/PE/AHF | 1068 (1045.87) | 1037 (1059.13) | 64.49 | 61.84 | | | | | |
Subset distribution (sex: male, N = 5411) | | | | | |
Variable | Class | Year: 2019 | Year: 2020 | Year: 2019 | Year: 2020 | χ2 | p | OR | OR {-95% CI} | OR {95% CI} | | | | | |
count [n] | count [n] | frequency [%] | frequency [%] | | | | | |
ACS | ACS | 1076 (1069.14) | 999 (1005.86) | 38.59 | 38.09 | 0.15 | 0.7010 | - | - | - | | | | | |
No ACS | 1712 (1718.86) | 1624 (1617.14) | 61.41 | 61.91 | | | | | |
Arrhythmia | Arrhythmia | 518 (530.7) | 512 (499.3) | 18.58 | 19.52 | 0.77 | 0.3787 | - | - | - | | | | | |
No arrhythmia | 2270 (2257.3) | 2111 (2123.7) | 81.42 | 80.48 | | | | | |
PE | PE | 61 (70.59) | 76 (66.41) | 2.19 | 2.90 | 2.76 | 0.9684 | 1.334 | 0.948 | 1.876 | | | | | |
No PE | 2727 (2717.41) | 2547 (2556.59) | 97.81 | 97.10 | | | | | |
AHF | AHF | 359 (291.63) | 207 (274.37) | 12.88 | 7.89 | 35.86 | < 0.00001 | 0.580 | 0.484 | 0.694 | | | | | |
No AHF | 2429 (2496.37) | 2416 (2348.63) | 87.12 | 92.11 | | | | | |
Other CVDs | Other CVDs | 774 (825.94) | 829 (777.06) | 27.76 | 31.61 | 9.57 | 0.0020 | 1.202 | 1.070 | 1.351 | | | | | |
ACS/arrhythmia/PE/AHF | 2014 (1962.06) | 1794 (1845.94) | 72.24 | 68.39 | | | | | |
Numbers in ‘()’ brackets indicate expected (estimated) counts. Significant odds ratios (ORs) are marked
Table 3
Time-related differences in CVD subtypes and CVD-related incidence of heart failure
Overall distribution (regardless of sex) |
Variable | Class | Year: 2019 | Year: 2020 | Year: 2019 | Year: 2020 | No stratification corrections | Generalized CMH (adjusted for stratification by sex) |
count [n] | count [n] | frequency [%] | frequency [%] | χ2 | p | OR | OR {-95% CI} | OR {95% CI} | p (each class) | χ2 | p | OR | OR {-95% CI} | OR {95% CI} | p (each class) |
ACS: type | NSTEMI | 607 (574.2) | 498 (530.8) | 42.09 | 37.36 | 18.73 | 0.0001 | 0.820 | 0.704 | 0.956 | 0.0109 | 18.63 | 0.0001 | 0.821 | 0.705 | 0.956 | 0.0112 |
STEMI | 583 (638.64) | 646 (590.36) | 40.43 | 48.46 | 1.385 | 1.192 | 1.610 | 0.00002 | 1.385 | 1.191 | 1.610 | < 0.00002 |
Unstable angina | 252 (229.16) | 189 (211.84) | 17.48 | 14.18 | 0.780 | 0.635 | 0.958 | 0.0176 | 0.780 | 0.636 | 0.958 | 0.0178 |
ACS: heart failure | Symptoms present | 216 (214.69) | 196 (197.31) | 14.95 | 14.76 | 0.020 | 0.8888 | - | - | - | - | 0.016 | 0.8981 | - | - | - | - |
No symptoms | 1229 (1230.31) | 1132 (1130.69) | 85.05 | 85.24 |
Arrhythmia: type | Atrial | 581 (577.41) | 566 (569.59) | 65.50 | 64.69 | 1.77 | 0.4122 | - | - | - | - | 1.81 | 0.4054 | - | - | - | - |
Ventricular | 110 (103.7) | 96 (102.3) | 12.40 | 10.97 |
Heart block, bradycardia | 196 (205.89) | 213 (203.11) | 22.10 | 24.34 |
Arrhythmia: heart failure | Symptoms present | 131 (142.44) | 159 (147.56) | 26.15 | 30.64 | 2.52 | 0.1122 | - | - | - | - | 2.62 | 0.1058 | - | - | - | - |
No symptoms | 370 (358.56) | 360 (371.44) | 73.85 | 69.36 |
PE: heart failure | Symptoms present | 15 (13.98) | 17 (18.02) | 14.02 | 12.32 | 0.15 | 0.6953 | - | - | - | - | 0.13 | 0.7182 | - | - | - | - |
No symptoms | 92 (93.02) | 121 (119.98) | 85.98 | 87.68 |
AHF: type | De novo | 55 (63.5) | 47 (38.5) | 21.65 | 30.52 | 4.02 | 0.0450 | 1.589 | 1.009 | 2.504 | - | 3.705 | 0.0542 | - | - | - | - |
CHF decompensation | 199 (190.5) | 107 (115.5) | 78.35 | 69.48 |
Subset distribution (sex: female) | | | | | | |
Variable | Class | Year: 2019 | Year: 2020 | Year: 2019 | Year: 2020 | χ2 | p | OR | OR {-95% CI} | OR {95% CI} | p (each class) | | | | | | |
count [n] | count [n] | frequency [%] | frequency [%] | | | | | | |
ACS: type | NSTEMI | 189 (180.96) | 156 (164.04) | 44.16 | 40.21 | 4.31 | 0.1160 | 0.850 | 0.644 | 1.123 | 0.2539 | | | | | | |
STEMI | 162 (176.24) | 174 (159.76) | 37.85 | 44.85 | 1.335 | 1.009 | 1.766 | 0.0427 | | | | | | |
Unstable angina | 77 (70.81) | 58 (64.19) | 17.99 | 14.95 | 0.801 | 0.552 | 1.163 | 0.2431 | | | | | | |
ACS: heart failure | Symptoms present | 71 (71.03) | 64 (63.97) | 16.78 | 16.80 | < 0.0001 | 0.9961 | - | - | - | - | | | | | | |
No symptoms | 352 (351.97) | 317 (317.03) | 83.22 | 83.20 | | | | | | |
Arrhythmia: type | Atrial | 282 (276.88) | 279 (284.12) | 73.82 | 71.17 | 2.47 | 0.2914 | - | - | - | - | | | | | | |
Ventricular | 35 (32.08) | 30 (32.92) | 9.16 | 7.65 | | | | | | |
Heart block, bradycardia | 65 (73.04) | 83 (74.96) | 17.02 | 21.17 | | | | | | |
Arrhythmia: heart failure | Symptoms present | 46 (50.74) | 58 (53.26) | 20.81 | 25.00 | 1.12 | 0.2897 | - | - | - | - | | | | | | |
No symptoms | 175 (170.26) | 174 (178.74) | 79.19 | 75.00 | | | | | | |
PE: heart failure | Symptoms present | 4 (4.69) | 7 (6.31) | 8.16 | 10.61 | 0.14 | 0.9046 | - | - | - | - | | | | | | |
No symptoms | 45 (44.31) | 59 (59.69) | 91.84 | 89.39 | | | | | | |
AHF: type | CHF decompensation | 65 (60.96) | 38 (42.04) | 74.71 | 63.33 | 2.19 | 0.1387 | - | - | - | - | | | | | | |
De novo | 22 (26.04) | 22 (17.96) | 25.29 | 36.67 | | | | | | |
Subset distribution (sex: male) | | | | | | |
Variable | Class | Year: 2019 | Year: 2020 | Year: 2019 | Year: 2020 | χ2 | p | OR | OR {-95% CI} | OR {95% CI} | p (each class) | | | | | | |
count [n] | count [n] | frequency [%] | frequency [%] | | | | | | |
ACS: type | NSTEMI | 418 (393.38) | 342 (366.62) | 41.22 | 36.19 | 14.43 | 0.0007 | 0.809 | 0.674 | 0.970 | 0.0222 | | | | | | |
STEMI | 421 (462.23) | 472 (430.77) | 41.52 | 49.95 | 1.406 | 1.176 | 1.680 | 0.0002 | | | | | | |
Unstable angina | 175 (158.39) | 131 (147.61) | 17.26 | 13.86 | 0.772 | 0.603 | 0.987 | 0.0386 | | | | | | |
ACS: heart failure | Symptoms present | 145 (143.78) | 132 (133.22) | 14.19 | 13.94 | 0.03 | 0.8737 | - | - | - | | | | | | | |
No symptoms | 877 (878.22) | 815 (813.78) | 85.81 | 86.06 | | | | | | |
Arrhythmia: type | Atrial | 299 (299.52) | 287 (286.48) | 59.21 | 59.42 | 0.33 | 0.8461 | - | - | - | | | | | | | |
Ventricular | 75 (72.07) | 66 (68.93) | 14.85 | 13.66 | | | | | | |
Heart block, bradycardia | 131 (133.41) | 130 (127.59) | 25.94 | 26.92 | | | | | | |
Arrhythmia: heart failure | Symptoms present | 85 (91.85) | 101 (94.15) | 30.36 | 35.19 | 1.50 | 0.2203 | - | - | - | | | | | | | |
No symptoms | 195 (188.15) | 186 (192.85) | 69.64 | 64.81 | | | | | | |
PE: heart failure | Symptoms present | 11 (9.37) | 10 (11.63) | 18.97 | 13.89 | 0.61 | 0.4343 | - | - | - | | | | | | | |
No symptoms | 47 (48.63) | 62 (60.37) | 81.03 | 86.11 | | | | | | |
AHF: type | CHF decompensation | 134 (129.89) | 69 (73.11) | 80.24 | 73.40 | 1.63 | 0.2023 | - | - | - | | | | | | | |
De novo | 33 (37.11) | 25 (20.89) | 19.76 | 26.60 | | | | | | |
Numbers in ‘()’ brackets indicate expected (estimated) counts. Significant odds ratios (ORs) are marked.