Prospective study of recovery from copperhead snake envenomation: an observational study

BMC Emergency Medicine

Table 16 Correlation between assessment items (Day 14 time point; absolute values shown)

Variable	Walking Speed	Grip Strength	Figure- of-8 Swelling	PSFS	WPAI:SHP Daily Activities Impairment	DASH	LEFS	PGIC	NSS	NPRS	SF-36v2 MCS	SF-36v2 PCS
Walking Speed	1	n/a	0.66	0.72	0.76	n/a	0.71	0.84	0.25	0.75	0.42	0.64
Grip Strength	--	1	0.65*	0.84	0.73	0.81	n/a	0.86	0.58	0.70	0.26	0.29
Figure-of-8 Swelling			1	0.06*	0.33	0.62	0.48	0.14*	0.08	0.08	0.37	0.08
PSFS				1	0.72	0.95	0.83	0.79	0.61	0.93	0.78	0.67
WPAI:SHP Daily Activities Impairment					1	0.72	0.80	0.55	0.61	0.80	0.21	0.59
DASH						1	n/a	0.64	0.55	0.88	0.03*	0.73
LEFS							1	0.92	0.65	0.93	0.15	0.88
PGIC								1	0.43	0.68	0.01*	0.52
NSS									1	0.75	0.08*	0.47
NPRS										1	0.02	0.71
SF-36v2 MCS											1	0.12*
SF-36v2 PCS												1

PSFS: Patient-Specific Functional Scale score [18,19]; WPAI:SHP: Work Productivity and Ability Impairment: Special Health Problem instrument, version 2 [21]; DASH: Disorders of the Arm, Shoulder, and Hand outcome measure [15,16]; PGIC: Patient’s Global Impression of Change, Scale 1 score [14]; LEFS: Lower Extremity Functional Scale [17]; NSS: Numeric Swelling Scale; NPRS: Numeric Pain Rating Scale; SF-36^® MCS and PCS: Mental and Physical Component Scores on the Medical Outcomes Study 36-item Short Form Health Survey version 2 (SF-36^®, v2) Acute Version instrument; n/a: not applicable; nd: no data or insufficient data to make this calculation. Because increasing values indicate improvement in some outcome measures and decrement in others, absolute values for correlations are shown. Results of the PGIC Scale 2 score are similar to the Scale 1 score (data not shown).
*Correlation is in the opposite direction from what is expected based on the design of the test (i.e. one test suggests worsening and the other suggests improvement).

ISSN: 1471-227X