Psychometric evaluation of the hypoparathyroidism symptom diary

Figures & data

Table 1 Demographic characteristics (N=52)

Characteristics	Statistics
Age (years), mean (SD), n
Mean (SD), n	51.3 (12.6), 52
Median, min-max	51.5, 24–78
Sex, n (%)
Male	8 (15.4)
Female	44 (84.6)
Educational level, n (%)
High school graduate or equivalent	7 (13.5)
Some college but no degree	13 (25.0)
College degree (eg, BA, BS)	16 (30.8)
Some graduate school but no degree	3 (5.8)
Graduate degree (eg, MS, MD, PhD)	13 (25.0)
Employment status, n (%)
Full-time	17 (32.7)
Part-time	9 (17.3)
Full-time homemaker	5 (9.6)
Unemployed	6 (11.5)
Disabled	9 (17.3)
Retired	6 (11.5)
Race/ethnicity, n (%) (check all that apply)
American Indian or Alaskan Native	1 (1.9)
African American	1 (1.9)
White	50 (96.2)
Hispanic	1 (1.9)
HPT-related clinical information
PGIS: How would you rate your hypoparathyroidism? n (%)
Very mild	1 (1.9)
Mild	9 (17.3)
Moderate	18 (34.6)
Severe	17 (32.7)
Very severe	7 (13.5)
Was your hypoparathyroidism caused by surgery? n (%)
Yes	45 (86.5)
No	6 (11.5)
Unknown	1 (1.9)
Years diagnosed with hypoparathyroidism, mean (SD)	10.5 (11.1), 52
Median, min-max	6.0, 1–51
Over the past year have you gone to urgent care or the emergency room due to your hypoparathyroidism? n (%)
Yes	18 (34.6)
Number of times: mean (SD), median, min-max	2.6 (1.4), 2.0, 1–6
No	34 (65.4)
Over the past year have you been admitted to the hospital due to your hypoparathyroidism? n (%)
Yes	9 (17.3)
Number of times: mean (SD), median, min-max	2.8 (2.4), 2.0, 1–8
No	43 (82.7)
Have you had kidney stones in the past 5 years? n (%)
Yes	10 (19.2)
No	42 (80.8)

Note: Percent calculated from non-missing responses.

Abbreviations: BA, Bachelor of Arts; BS, Bachelor of Science; HPT, hypoparathyroidism; MD, Doctor of Medicine; MS, Master of Science; PGIS, patients’ global impression of symptom severity; PhD, Doctor of Philosophy.

Table 2 Descriptive statistics for HPT-SD and other PRO measures (N=52)

Measure and items	n	Mean (SD)	Median	Min-Max	Missing (%)
HPT-SD
Item 1. Muscle cramps	52	4.0 (2.6)	4.5	0–9	0 (0)
Item 2. Tingling	52	1.4 (0.8)	1.0	0–3	0 (0)
Item 3. Numbness	52	1.2 (1.0)	1.0	0–3	0 (0)
Item 4. Muscle spasms or twitching	52	1.5 (1.0)	1.0	0–3	0 (0)
Item 5. Feelings of heaviness in arms or legs	52	1.3 (1.0)	1.0	0–4	0 (0)
Item 6. Physical fatigue	52	2.4 (0.9)	2.0	0–4	0 (0)
Item 7. Slowed or confused thinking (brain fog)	52	1.8 (1.1)	2.0	0–4	0 (0)
Item 8. Anxiety	52	1.7 (1.2)	1.5	0–4	0 (0)
Item 9. Sadness or depression	52	1.3 (1.1)	1.0	0–4	0 (0)
Item 10. Impact sleep	52	1.0 (0.7)	1.0	0–2	0 (0)
Item 11. Impact exercise	52	1.4 (0.8)	2.0	0–2	0 (0)
Item 12. Impact work	51	0.9 (0.7)	1.0	0–2	1 (1.9)
Item 13. Impact relationships	52	0.8 (0.7)	1.0	0–2	0 (0)
HPT-SD Symptom subscale score
(1: Muscle crampsa; 2: Tingling; 3: Numbness; 4: Muscle spasms or twitching; 5: Feelings of heaviness in arms; 6: Physical fatigue; 7: Slowed or confused thinking)	52	1.6 (0.8)	1.5	0.3–3.1	0 (0)
HPT-SD Impact subscale score
(10: Sleep; 11: Exercise; 12: Work; 13: Relationships)	51	1.0 (0.6)	1.0	0.0–2.0	1 (1.9)
FACIT-Fatigue	52	20.3 (12.9)	17.0	0–48	0 (0)
FACT-Cog
Perceived cognitive impairments	52	37.9 (18.5)	39.5	3–69	0 (0)
Impact of perceived cognitive impairments on quality of life	52	5.6 (5.3)	4.5	0–16	0 (0)
Comments from others	52	12.5 (4.0)	14.0	0–16	0 (0)
Perceived cognitive abilities	52	13.9 (6.5)	12.8	0–28	0 (0)
HADS
Depression	52	8.2 (4.9)	9.0	1–19	0 (0)
Anxiety	52	9.8 (3.9)	9.5	0–17	0 (0)

Note:

a To calculate the HPT-SD Symptom subscale, item 1 was rescaled from an 11-point response scale to a 5-point response scale ranging from 0 to 4.

Abbreviations: FACIT-Fatigue, Functional Assessment of Chronic Illness Therapy–Fatigue; FACT-Cog, Functional Assessment in Cancer Therapy–Cognitive Function; HADS, Hospital Anxiety and Depression Scale; HPT-SD, Hypoparathyroidism Symptom Diary; PRO, patient-reported outcome.

Table 3 HPT-SD item-level response distributions (N=52)

Symptom itemsa	Response option, n (%)
	None	Mild	Moderate	Severe	Very severe	Missing
Item 2. Tingling, n (%)	7 (13.5)	23 (44.2)	18 (34.6)	4 (7.7)	0 (0)	0 (0)
Item 3. Numbness, n (%)	15 (28.8)	20 (38.5)	11 (21.2)	6 (11.5)	0 (0)	0 (0)
Item 4. Muscle spasms or twitching, n (%)	7 (13.5)	23 (44.2)	11 (21.2)	11 (21.2)	0 (0)	0 (0)
Item 5. Feelings of heaviness in arms or legs, n (%)	13 (25.0)	16 (30.8)	16 (30.8)	6 (11.5)	1 (1.9)	0 (0)
Item 6. Physical fatigue, n (%)	2 (3.8)	3 (5.8)	26 (50.0)	15 (28.8)	6 (11.5)	0 (0)
Item 7. Slowed or confused thinking (brain fog), n (%)	7 (13.5)	15 (28.8)	15 (28.8)	12 (23.1)	3 (5.8)	0 (0)
Item 8. Anxiety, n (%)	7 (13.5)	19 (36.5)	12 (23.1)	10 (19.2)	4 (7.7)	0 (0)
Item 9. Sadness or depression, n (%)	15 (28.8)	16 (30.8)	14 (26.9)	5 (9.6)	2 (3.8)	0 (0)
Impact items	Response option, n (%)
	Not at all		Somewhat		Very much	Missing
Item 10. Impact sleep, n (%)	14 (26.9)		24 (46.2)		14 (26.9)	0 (0)
Item 11. Impact exercise, n (%)	9 (17.3)		15 (28.8)		28 (53.8)	0 (0)
Item 12. Impact work, n (%)	16 (31.4)		24 (47.1)		11 (21.6)	1 (1.9)
Item 13. Impact relationships, n (%)	22 (42.3)		21 (40.4)		9 (17.3)	0 (0)

Notes: Percent calculated from non-missing responses.

a Item 1 was initially scored on an 11-point NRS (0 [no muscle cramps] to 10 [worst possible muscle cramps]), with distributions for the response options as follows: 0: seven patients (13.5%); 1: four patients (7.7%); 2: four patients (7.7%); 3: nine patients (17.3%); 4: two patients (3.8%); 5: seven patients (13.5%); 6: ten patients (19.2%); 7: seven patients (13.5%); 8: 0 patients; 9: two patients (3.8%); 10: 0 patients.

Abbreviations: HPT-SD, Hypoparathyroidism Symptom Diary; NRS, numeric rating scale.

Table 4 HPT-SD inter-item correlations (n=51–52)

HPT-SD items	Correlation coefficient, r
	HPT-SD item
	1	2	3	4	5	6	7	8	9	10	11	12	13
Item 1. Muscle cramps	–
Item 2. Tingling	0.55	–
Item 3. Numbness	0.60	0.74	–
Item 4. Muscle spasms or twitching	0.75	0.72	0.71	–
Item 5. Feelings of heaviness in arms or legs	0.55	0.61	0.72	0.64	–
Item 6. Physical fatigue	0.50	0.66	0.69	0.57	0.56	–
Item 7. Slowed or confused thinking (brain fog)	0.57	0.43	0.53	0.55	0.68	0.70	–
Item 8. Anxiety	0.30	0.42	0.50	0.48	0.55	0.51	0.63	–
Item 9. Sadness or depression	0.34	0.47	0.49	0.49	0.53	0.57	0.63	0.81	–
Item 10. Impact sleep	0.45	0.50	0.35	0.62	0.32	0.29	0.39	0.50	0.59	–
Item 11. Impact exercise	0.57	0.53	0.59	0.69	0.52	0.63	0.63	0.51	0.69	0.49	–
Item 12. Impact work	0.49	0.62	0.63	0.46	0.66	0.70	0.60	0.61	0.59	0.48	0.67	–
Item 13. Impact relationships	0.24	0.57	0.58	0.53	0.52	0.52	0.56	0.57	0.73	0.45	0.66	0.62	–

Abbreviation: HPT-SD, Hypoparathyroidism Symptom Diary.

Table 5 Construct validity correlations (n=51–52)

HPT-SD score	Correlation coefficient (r)
	FACIT-Fatigue	FACT-Cog impairments	FACT- Cog impact	FACT-Cog comments	FACT- Cog abilities	HADS depression	HADS anxiety
Item 1. Muscle cramps	–0.53	–0.41	–0.59	–0.37	–0.45	0.33	0.33
Item 2. Tingling	–0.51	–0.34	–0.46	–0.29	–0.31	0.42	0.36
Item 3. Numbness	–0.50	–0.40	–0.54	–0.42	–0.48	0.47	0.49
Item 4. Muscle spasms or twitching	–0.54	–0.43	–0.61	–0.44	–0.37	0.40	0.37
Item 5. Feelings of heaviness in arms or legs	–0.61	–0.57	–0.54	–0.52	–0.64	0.50	0.47
Item 6. Physical fatigue	–0.78	–0.48	–0.59	–0.43	–0.46	0.49	0.34
Item 7. Slowed or confused thinking (brain fog)	–0.57	–0.68	–0.58	–0.68	–0.62	0.49	0.30
Item 8. Anxiety	–0.53	–0.57	–0.49	–0.61	–0.57	0.64	0.63
Item 9. Sadness or depression	–0.59	–0.49	–0.54	–0.54	–0.52	0.63	0.48
Item 10. Impact sleep	–0.40	–0.44	–0.52	–0.31	–0.35	0.28	0.23
Item 11. Impact exercise	–0.67	–0.59	–0.59	–0.62	–0.49	0.62	0.51
Item 12. Impact work	–0.67	–0.59	–0.75	–0.53	–0.57	0.54	0.58
Item 13. Impact relationships	–0.51	–0.45	–0.59	–0.53	–0.47	0.52	0.52
HPT-SD Symptom subscale score	–0.70	–0.57	–0.67	–0.55	–0.58	0.54	0.46
(1: Muscle crampsa; 2: Tingling; 3: Numbness; 4: Muscle spasms or twitching; 5: Feelings of heaviness in arms; 6: Physical fatigue; 7: Slowed or confused thinking)
HPT-SD Impact subscale score	–0.66	–0.60	–0.71	–0.55	–0.54	0.57	0.54
(10: Sleep; 11: Exercise; 12: Work; 13: Relationships)

Notes: Correlations in bold indicate a priori hypotheses.

a To calculate the HPT-SD Symptom subscale, item 1 was rescaled from an 11-point response scale to a 5-point response scale ranging from 0 to 4.

Abbreviations: FACIT-Fatigue, Functional Assessment of Chronic Illness Therapy–Fatigue; FACT-Cog, Functional Assessment in Cancer Therapy–Cognitive Function; HADS, Hospital Anxiety and Depression Scale; HPT-SD, Hypoparathyroidism Symptom Diary.

Table S1 Treatment characteristics (N=52)

	Statistics
Calcium type, n (%)a
Calcium carbonate	24 (47.1)
Calcium citrate	24 (46.2)
Calcium gluconate	0 (0)
Other	12 (23.5)
Do not know	0 (0)
Vitamin D type, n (%)a
Over the counter	10 (19.2)
Ergocalciferol	3 (5.9)
Calcitriol	45 (86.5)
Other	6 (11.8)
Do not know	0 (0)
Over the past 6 months have you taken additional calcium/vitamin D due to symptoms? n (%)
Yes	42 (80.8)
No	10 (19.2)
Have you had a blood test of your calcium level in the past year? n (%)
Yes	51 (98.1)
Number of blood tests: mean (SD), median, min-max	8.6 (13.0), 4.0, 1–60
No	1 (1.9)
Was your most recent blood calcium level within normal range, n (%)b
Yes	29 (55.8)
No	23 (44.2)
Have you had a urine test of your calcium level in the past year? n (%)
Yes	25 (48.1)
Number of urine tests: mean (SD), median, min-max	1.7 (1.5), 1.0, 0–6
No	27 (51.9)
Was your most recent urine calcium level within normal range, n (%)c
Yes	18 (34.6)
No	16 (30.8)
Not applicable	18 (34.6)

Notes: Percent calculated from non-missing responses.

a Percentages may not total 100 because patients checked all options that applied.

b The most recent blood calcium level may or may not have been measured in the past year.

c The most recent urine calcium level may or may not have been measured in the past year.

Table S2 Known-groups results

HPT-SD score	Patient-reported HPT severitya = very mild or mild		Patient-reported HPT severity = severea or very severe		P-valueb
	N	Mean (SD)	N	Mean (SD)
Item 1. Muscle cramps	10	1.0 (1.1)	24	4.9 (2.2)	<0.0001
Item 2. Tingling	10	1.0 (0.5)	24	1.6 (0.9)	0.0698
Item 3. Numbness	10	0.4 (0.5)	24	1.5 (1.1)	0.0039
Item 4. Muscle spasms or twitching	10	0.7 (0.5)	24	1.9 (1.1)	0.0024
Item 5. Feelings of heaviness in arms or legs	10	0.6 (0.7)	24	1.5 (1.1)	0.0277
Item 6. Physical fatigue	10	1.7 (0.7)	24	2.7 (1.0)	0.0084
Item 7. Slowed or confused thinking (brain fog)	10	0.7 (0.8)	24	2.0 (1.1)	0.0018
Item 8. Anxiety	10	0.9 (0.9)	24	2.0 (1.3)	0.0223
Item 9. Sadness or depression	10	0.5 (0.7)	24	1.6 (1.2)	0.0153
Item 10. Impact sleep	10	0.6 (0.7)	24	1.3 (0.7)	0.0236
Item 11. Impact exercise	10	0.5 (0.7)	24	1.7 (0.5)	<0.0001
Item 12. Impact work	10	0.3 (0.5)	23	1.2 (0.7)	0.0005
Item 13. Impact relationships	10	0.2 (0.4)	24	1.0 (0.8)	0.0073
HPT-SD symptom subscale score
(1: Muscle crampsc; 2: Tingling; 3: Numbness; 4: Muscle spasms or twitching; 5: Feelings of heaviness in arms; 6: Physical fatigue; 7: Slowed or confused thinking)	10	0.8 (0.3)	24	1.9 (0.8)	0.0002
HPT-SD impact subscale score
(10: Sleep; 11: Exercise; 12: Work; 13: Relationships)	10	0.4 (0.5)	23	1.3 (0.5)	<0.0001

Notes:

a Groups based on responses to PGIS.

b ANOVA tests “very mild to mild” subgroup with “severe to very severe” subgroup.

c To calculate the HPT-SD Symptom subscale, item 1 was rescaled from an 11-point response scale to a 5-point response scale ranging from 0 to 4.

Abbreviations: HPT, hypoparathyroidism; HPT-SD, Hypoparathyroidism Symptom Diary; PGIS, patients’ global impression of symptom severity.